diff --git a/include/binaries b/include/binaries
index 0fbefe46..5812003f 100644
--- a/include/binaries
+++ b/include/binaries
@@ -49,7 +49,7 @@
 
         # Test if our PATH variable provides a set of paths. If so, reverse the order. If we discover the same binary
         # multiple times, the one first in PATH should be used.
-        if [ ! -z "${PATH}" ]; then
+        if [ -n "${PATH}" ]; then
             PATH_REVERSED=$(echo ${PATH} | awk -F: '{ for (i=NF; i>1; i--) printf("%s ",$i); print $1; }')
             BIN_PATHS=$(echo "${PATH_REVERSED}" | tr ':' ' ')
         fi
@@ -84,7 +84,7 @@
                     LogText "Result: directory exists, but is actually a symlink"
                     ShowSymlinkPath ${SCANDIR}
                     if [ ${FOUNDPATH} -eq 1 ]; then
-                        if [ ! -z "${SYMLINK}" -a -d ${SYMLINK} ]; then
+                        if [ -n "${SYMLINK}" -a -d ${SYMLINK} ]; then
                             # Set path to new location
                             LogText "Result: found the path behind this symlink (${SCANDIR} --> ${sFILE})"
                             ORGPATH="${SCANDIR}"
@@ -100,7 +100,7 @@
                 # Add a space to make sure we discover a related directory if it was already scanned
                 # The grep -v is to prevent a match /usr/bin in something like /usr/bin/core_perl
                 FIND=$(echo ${BINARY_PATHS_FOUND} | grep ", ${SCANDIR}" | grep -v ", ${SCANDIR}/")
-                if [ ! -z "${FIND}" ]; then
+                if [ -n "${FIND}" ]; then
                     SKIPDIR=1; LogText "Result: Skipping this directory as it was already scanned"
                 fi
 
@@ -273,7 +273,7 @@
                     done
                 else
                     LogText "Result: Directory ${SCANDIR} skipped"
-                    if [ ! -z "${ORGPATH}" ]; then TEXT="${ORGPATH} (links to ${SCANDIR})"; else TEXT="${SCANDIR}"; fi
+                    if [ -n "${ORGPATH}" ]; then TEXT="${ORGPATH} (links to ${SCANDIR})"; else TEXT="${SCANDIR}"; fi
                 fi
             else
                 LogText "Result: Directory ${SCANDIR} does NOT exist"
diff --git a/include/functions b/include/functions
index c8f689e7..80096f50 100644
--- a/include/functions
+++ b/include/functions
@@ -267,16 +267,16 @@
         if [ ${RUN_UPDATE_CHECK} -eq 1 ]; then
             LYNIS_LV_RECORD="lynis-latest-version.cisofy.com."
             FIND=$(which dig 2> /dev/null | grep -v "no [^ ]* in")
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 PROGRAM_LV=$(dig +short +time=3 -t txt lynis-latest-version.cisofy.com 2> /dev/null | grep -v "connection timed out" | sed 's/[".]//g' | grep "^[1-9][0-9][0-9]$")
             else
                 FIND=$(which host 2> /dev/null | grep -v "no [^ ]* in ")
-                if [ ! -z "${FIND}" ]; then
+                if [ -n "${FIND}" ]; then
                     PROGRAM_LV=$(host -t txt -W 3 lynis-latest-version.cisofy.com 2> /dev/null | grep -v "connection timed out" | awk '{ if ($1=="lynis-latest-version.cisofy.com" && $3=="text") { print $4 }}' | sed 's/"//g' | grep "^[1-9][0-9][0-9]$")
                     if [ "${PROGRAM_LV}" = "" ]; then PROGRAM_LV=0; fi
                 else
                     FIND=$(which drill 2> /dev/null | grep -v "no [^ ]* in ")
-                    if [ ! -z "${FIND}" ]; then
+                    if [ -n "${FIND}" ]; then
                         PROGRAM_LV=$(drill txt ${LYNIS_LV_RECORD} | awk '{ if ($1=="lynis-latest-version.cisofy.com." && $4=="TXT") { print $5 }}' | tr -d '"' | grep "^[1-9][0-9][0-9]$")
                         if [ -z "${PROGRAM_LV}" ]; then PROGRAM_LV=0; fi
                     else
@@ -530,7 +530,7 @@
             fi
         fi
 
-        if [ ! -z "${TEXT}" ]; then
+        if [ -n "${TEXT}" ]; then
             SHOW=0
             if [ ${SHOW_WARNINGS_ONLY} -eq 1 ]; then
                 if [ "${RESULT}" = "WARNING" ]; then SHOW=1; fi
@@ -571,7 +571,7 @@
         ${ECHOCMD} ""
         ${ECHOCMD} "${WARNING}Error${NORMAL}: ${BOLD}$1${NORMAL}"
         ${ECHOCMD} ""
-        if [ ! -z "${EXITCODE}" ]; then ExitCustom ${EXITCODE}; fi
+        if [ -n "${EXITCODE}" ]; then ExitCustom ${EXITCODE}; fi
     }
 
 
@@ -747,12 +747,12 @@
         exitcode=1
         file=$1
         find=""
-        if [ ! -z "${DPKGBINARY}" ]; then
+        if [ -n "${DPKGBINARY}" ]; then
             find=$(${DPKGBINARY} -S "${file}" 2> /dev/null | ${AWKBINARY} -F: '{print $1}')
-        elif [ ! -z "${RPMBINARY}" ]; then
+        elif [ -n "${RPMBINARY}" ]; then
             find=$(${RPMBINARY} -qf "${file}" 2> /dev/null | ${AWKBINARY} -F- '{print $1}')
         fi
-        if [ ! -z "${find}" ]; then
+        if [ -n "${find}" ]; then
             LogText "Result: file '${file}' belongs to package (${find})"
             exitcode=0
         else
@@ -805,7 +805,7 @@
         # Check for symlink
         if [ -L "${escaped_file}" ]; then
             ShowSymlinkPath ${escaped_file}
-            if [ ! -z "${SYMLINK}" ]; then escaped_file="${SYMLINK}"; fi
+            if [ -n "${SYMLINK}" ]; then escaped_file="${SYMLINK}"; fi
         fi
 
         # Only check the file if it isn't a symlink (after previous check)
@@ -863,7 +863,7 @@
             return 2
         fi
 
-        if [ ! -z "${HOSTID}" -a ! -z "${HOSTID2}" ]; then
+        if [ -n "${HOSTID}" -a -n "${HOSTID2}" ]; then
             Debug "Skipping creation of host identifiers, as they are already configured (via profile)"
             return 2
         fi
@@ -936,7 +936,7 @@
                 "HP-UX")
                     FIND=$(nwmgr -q info -c lan0 2> /dev/null | awk '{ if ($1=="MAC" && $2=="Address") { print $4 }}')
                     if HasData "${FIND}"; then
-                        if [ ! -z "${OPENSSLBINARY}" ]; then
+                        if [ -n "${OPENSSLBINARY}" ]; then
                             HOSTID=$(echo ${FIND} | ${OPENSSLBINARY} sha -sha1 | awk '{ print $2 }')
                         else
                             ReportException "GetHostID" "No openssl binary available on this HP-UX system"
@@ -954,7 +954,7 @@
                     # ip -br link show up | sort | awk '$2=="UP" && $3 ~ /^[a-f0-9][a-f0-9]:/ {print $3}'
 
                     # Use ifconfig
-                    if [ ! -z "${IFCONFIGBINARY}" ]; then
+                    if [ -n "${IFCONFIGBINARY}" ]; then
                         # Determine if we have the eth0 interface (not all Linux distro have this, e.g. Arch)
                         HASETH0=$(${IFCONFIGBINARY} | grep "^eth0")
                         # Check if we can find it with HWaddr on the line
@@ -982,7 +982,7 @@
                             fi
                         fi
 
-                    elif [ ! -z "${IPBINARY}" ]; then
+                    elif [ -n "${IPBINARY}" ]; then
                         # Determine if we have the common available eth0 interface
                         FIND=$(${IPBINARY} addr show eth0 2> /dev/null | egrep "link/ether " | head -1 | awk '{ print $2 }' | tr '[:upper:]' '[:lower:]')
                         if IsEmpty "${FIND}"; then
@@ -1015,10 +1015,10 @@
                         ReportException "GetHostID" "No MAC address returned on macOS"
                     fi
                     LYNIS_HOSTID2_PART1=$(hostname -s)
-                    if [ ! -z "${LYNIS_HOSTID2_PART1}" ]; then
+                    if [ -n "${LYNIS_HOSTID2_PART1}" ]; then
                         LogText "Info: using hostname ${LYNIS_HOSTID2_PART1}"
                         LYNIS_HOSTID2_PART2=$(sysctl -n kern.uuid 2> /dev/null)
-                        if [ ! -z "${LYNIS_HOSTID2_PART2}" ]; then
+                        if [ -n "${LYNIS_HOSTID2_PART2}" ]; then
                             LogText "Info: using UUID ${LYNIS_HOSTID2_PART2}"
                         else
                             LogText "Info: could not create HOSTID2 as kern.uuid sysctl key is missing"
@@ -1143,17 +1143,17 @@
             fi
 
             STRING_TO_HASH=""
-            if [ ${FOUND} -eq 1 -a ! -z "${DATA_SSH}" ]; then
+            if [ ${FOUND} -eq 1 -a -n "${DATA_SSH}" ]; then
                 LogText "Using SSH public key to create the second host identifier"
                 STRING_TO_HASH="${DATA_SSH}"
             else
-                if [ ! -z "${MACHINEID}" ]; then
+                if [ -n "${MACHINEID}" ]; then
                     LogText "Using the machine ID to create the second host identifier"
                     STRING_TO_HASH="${MACHINEID}"
                 fi
             fi
             # Check if we have a string to turn into a host identifier
-            if [ ! -z "${STRING_TO_HASH}" ]; then
+            if [ -n "${STRING_TO_HASH}" ]; then
                 # Create hashes
                 if [ ! "${SHA256SUMBINARY}" = "" ]; then
                     HASH2=$(echo ${STRING_TO_HASH} | ${SHA256SUMBINARY} | awk '{ print $1 }')
@@ -1172,7 +1172,7 @@
         if [ -z "${HOSTID}" ]; then
             ReportException "GetHostID" "No unique host identifier could be created."
             return 1
-        elif [ ! -z "${HOSTID2}" ]; then
+        elif [ -n "${HOSTID2}" ]; then
             return 0
         fi
     }
@@ -1228,7 +1228,7 @@
 
     HasData() {
         if [ $# -eq 1 ]; then
-            if [ ! -z "$1" ]; then return 0; else return 1; fi
+            if [ -n "$1" ]; then return 0; else return 1; fi
         else
             ExitFatal "Function HasData called without parameters - look in log to determine where this happened, or use sh -x lynis to see all details."
         fi
@@ -1386,7 +1386,7 @@
         if [ -z "${search}" ]; then ExitFatal "Missing process to search for when using IsRunning function"; fi
         RUNNING=0
         # AIX does not fully support pgrep options, so using ps instead
-        if [ ! -z "${PGREPBINARY}" -a ! "${OS}" = "AIX" ]; then
+        if [ -n "${PGREPBINARY}" -a ! "${OS}" = "AIX" ]; then
             FIND=$(${PGREPBINARY} ${pgrep_options} "${search}" | ${TRBINARY} '\n' ' ')
         else
             if [ -z "${PSOPTIONS}" ]; then
@@ -1402,7 +1402,7 @@
             FIND=$(${PSBINARY} ${PSOPTIONS} | egrep "( |/)${search}" | grep -v "grep")
         fi
 
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             RUNNING=1
             LogText "IsRunning: process '${search}' found (${FIND})"
             return 0
@@ -1421,7 +1421,7 @@
 
     IsNotebook() {
         FIND=$(which laptop-detect 2> /dev/null | grep -v "no [^ ]* in ")
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             Debug "Testing if we are a notebook"
             laptop-detect
             if [ $? -eq 0 ]; then SYSTEM_IS_NOTEBOOK=1; Debug "System is a notebook according to laptop-detect"
@@ -1535,7 +1535,7 @@
             if [ -x /usr/bin/systemd-detect-virt ]; then
                 LogText "Test: trying to guess virtualization technology with systemd-detect-virt"
                 FIND=$(/usr/bin/systemd-detect-virt)
-                if [ ! -z "${FIND}" ]; then
+                if [ -n "${FIND}" ]; then
                     LogText "Result: found ${FIND}"
                     SHORT="${FIND}"
                 fi
@@ -1552,7 +1552,7 @@
             if [ -x /usr/bin/lscpu ]; then
                 LogText "Test: trying to guess virtualization with lscpu"
                 FIND=$(lscpu | grep -i "^Hypervisor Vendor" | awk -F: '{ print $2 }' | sed 's/ //g')
-                if [ ! -z "${FIND}" ]; then
+                if [ -n "${FIND}" ]; then
                     LogText "Result: found ${FIND}"
                     SHORT="${FIND}"
                 else
@@ -1576,7 +1576,7 @@
             if [ ! "${DMIDECODE_BINARY}" = "" -a ${PRIVILEGED} -eq 1 ]; then
                 LogText "Test: trying to guess virtualization with dmidecode"
                 FIND=$(/usr/sbin/dmidecode -s system-product-name | awk '{ print $1 }')
-                if [ ! -z "${FIND}" ]; then
+                if [ -n "${FIND}" ]; then
                     LogText "Result: found ${FIND}"
                     SHORT="${FIND}"
                 else
@@ -1820,24 +1820,24 @@
             Fatal "Incorrect usage of PackageIsInstalled function"
         fi
 
-        if [ ! -z "${DNFBINARY}" ]; then
+        if [ -n "${DNFBINARY}" ]; then
             output=$(${DNFBINARY} --quiet --cacheonly --noplugins --assumeno info --installed ${package} > /dev/null 2>&1)
             exit_code=$?
-        elif [ ! -z "${DPKGBINARY}" ]; then
+        elif [ -n "${DPKGBINARY}" ]; then
             output=$(${DPKGBINARY} -l ${package} 2> /dev/null | ${GREPBINARY} "^ii")
             exit_code=$?
-        elif [ ! -z "${EQUERYBINARY}" ]; then
+        elif [ -n "${EQUERYBINARY}" ]; then
             output=$(${EQUERYBINARY} --quiet ${package} > /dev/null 2>&1)
             exit_code=$?  # 0=package installed, 3=package not installed
-        elif [ ! -z "${PKG_BINARY}" ]; then
+        elif [ -n "${PKG_BINARY}" ]; then
             output=$(${PKG_BINARY} -N info ${package} >/dev/null 2>&1)
             exit_code=$?  # 0=package installed, 70=invalid package
-        elif [ ! -z "${RPMBINARY}" ]; then
+        elif [ -n "${RPMBINARY}" ]; then
             output=$(${RPMBINARY} --quiet -q ${package} > /dev/null 2>&1)
             exit_code=$?
-        elif [ ! -z "${ZYPPERBINARY}" ]; then
+        elif [ -n "${ZYPPERBINARY}" ]; then
             output=$(${ZYPPERBINARY} --quiet --non-interactive search --installed -i ${PACKAGE} 2> /dev/null | grep "^i")
-            if [ ! -z "${output}" ]; then exit_code=0; else exit_code=1; fi
+            if [ -n "${output}" ]; then exit_code=0; else exit_code=1; fi
         else
             ReportException "PackageIsInstalled:01"
         fi
@@ -2363,7 +2363,7 @@
         if [ ${SKIPTEST} -eq 0 -a "${TEST_WEIGHT}" = "M" -a "${SCAN_TEST_MEDIUM}" = "NO" ]; then SKIPTEST=1; SKIPREASON="Test to system intensive for scan mode (M)"; fi
 
         # Test if our OS is the same as the requested OS (can be multiple values)
-        if [ ${SKIPTEST} -eq 0 -a ! -z "${TEST_NEED_OS}" ]; then
+        if [ ${SKIPTEST} -eq 0 -a -n "${TEST_NEED_OS}" ]; then
             HASMATCH=0
             for I in ${TEST_NEED_OS}; do
                 if [ "${I}" = "${OS}" ]; then HASMATCH=1; fi
@@ -2375,12 +2375,12 @@
         fi
 
         # Skip test when it belongs to another category (default is 'all')
-        if [ ${SKIPTEST} -eq 0 -a ! -z "${TEST_CATEGORY_TO_CHECK}" -a ! "${TEST_CATEGORY_TO_CHECK}" = "all" -a ! "${TEST_CATEGORY}" = "${TEST_CATEGORY_TO_CHECK}" ]; then
+        if [ ${SKIPTEST} -eq 0 -a -n "${TEST_CATEGORY_TO_CHECK}" -a ! "${TEST_CATEGORY_TO_CHECK}" = "all" -a ! "${TEST_CATEGORY}" = "${TEST_CATEGORY_TO_CHECK}" ]; then
             SKIPTEST=1; SKIPREASON="Incorrect category (${TEST_CATEGORY_TO_CHECK} only)"
         fi
 
         # Check for correct hardware platform
-        if [ ${SKIPTEST} -eq 0 -a ! -z "${TEST_NEED_PLATFORM}" -a ! "${HARDWARE}" = "${TEST_NEED_PLATFORM}" ]; then SKIPTEST=1; SKIPREASON="Incorrect hardware platform"; fi
+        if [ ${SKIPTEST} -eq 0 -a -n "${TEST_NEED_PLATFORM}" -a ! "${HARDWARE}" = "${TEST_NEED_PLATFORM}" ]; then SKIPTEST=1; SKIPREASON="Incorrect hardware platform"; fi
 
         # Not all prerequisites met, like missing tool
         if [ ${SKIPTEST} -eq 0 -a "${PREQS_MET}" = "NO" ]; then SKIPTEST=1; if [ -z "${SKIPREASON}" ]; then SKIPREASON="Prerequisites not met (ie missing tool, other type of Linux distribution)"; fi; fi
@@ -2462,7 +2462,7 @@
     # Remove PID file
     RemovePIDFile() {
         # Test if PIDFILE is defined, before checking file presence
-        if [ ! -z "${PIDFILE}" ]; then
+        if [ -n "${PIDFILE}" ]; then
             if [ -f "${PIDFILE}" ]; then
                 rm -f "${PIDFILE}"
                 LogText "PID file removed (${PIDFILE})"
@@ -2486,7 +2486,7 @@
             for FILE in ${TEMP_FILES}; do
                 # Temporary files should be in /tmp
                 TMPFILE=$(echo ${FILE} | egrep "^/tmp/lynis" | grep -v "\.\.")
-                if [ ! -z "${TMPFILE}" ]; then
+                if [ -n "${TMPFILE}" ]; then
                     if [ -f "${TMPFILE}" ]; then
                         LogText "Action: removing temporary file ${TMPFILE}"
                         rm -f "${TMPFILE}"
@@ -2887,7 +2887,7 @@
                 # Check if we can find the main type (with or without brackets)
                 LogText "Test: search string ${STRING} in file ${FILE}"
                 FIND=$(egrep "${STRING}" ${FILE})
-                if [ ! -z "${FIND}" ]; then
+                if [ -n "${FIND}" ]; then
                     LogText "Result: found search string '${STRING}'"
                     if [ ${MASK_LOG} -eq 0 ]; then LogText "Full string returned: ${FIND}"; fi
                     RETVAL=0
@@ -3285,7 +3285,7 @@
     ################################################################################
 
     ViewGroups() {
-        if [ ! -z "${INCLUDEDIR}" ]; then
+        if [ -n "${INCLUDEDIR}" ]; then
             for I in $(ls ${INCLUDEDIR}/tests_* | xargs -n 1 basename | sed 's/tests_//' | grep -v "custom.template"); do
               echo "${I}"
             done
diff --git a/include/helper_audit_dockerfile b/include/helper_audit_dockerfile
index 3d18556f..b3eff024 100644
--- a/include/helper_audit_dockerfile
+++ b/include/helper_audit_dockerfile
@@ -59,11 +59,11 @@ fi
         IS_ALPINE=$(echo ${IMAGE} | grep -i alpine)
         IS_LATEST=$(echo ${TAG} | grep -i latest)
 
-        if [ ! -z "${IS_DEBIAN}" ]; then IMAGE="debian"; fi
-        if [ ! -z "${IS_FEDORA}" ]; then IMAGE="fedora"; fi
-        if [ ! -z "${IS_UBUNTU}" ]; then IMAGE="ubuntu"; fi
-        if [ ! -z "${IS_ALPINE}" ]; then IMAGE="alpine"; fi
-        if [ ! -z "${IS_LATEST}" ]; then
+        if [ -n "${IS_DEBIAN}" ]; then IMAGE="debian"; fi
+        if [ -n "${IS_FEDORA}" ]; then IMAGE="fedora"; fi
+        if [ -n "${IS_UBUNTU}" ]; then IMAGE="ubuntu"; fi
+        if [ -n "${IS_ALPINE}" ]; then IMAGE="alpine"; fi
+        if [ -n "${IS_LATEST}" ]; then
             ReportWarning "dockerfile" "latest TAG used. Specifying a targeted OS image and version is better for reproducible results."
         fi
 
diff --git a/include/helper_show b/include/helper_show
index d1086378..8f906d99 100644
--- a/include/helper_show
+++ b/include/helper_show
@@ -154,7 +154,7 @@ if [ $# -gt 0 ]; then
                 # Check also for gzipped changelog
                 elif [ -f ${FILEPATH}/changelog.gz ]; then
                     ZCAT=$(which zcat 2> /dev/null | grep -v "no [^ ]* in ")
-                    if [ ! -z "${ZCAT}" ]; then
+                    if [ -n "${ZCAT}" ]; then
                         CreateTempFile
                         CHANGELOG="${TEMP_FILE}"
                         LogText "Result: found gzipped changelog in ${FILEPATH}"
@@ -164,9 +164,9 @@ if [ $# -gt 0 ]; then
                         DisplayError "Could not find zcat utility to use on gzipped changelog"
                     fi
                 fi
-                if [ ! -z "${CHANGELOG}" ]; then LogText "Result: found changelog file: ${CHANGELOG}"; break; fi
+                if [ -n "${CHANGELOG}" ]; then LogText "Result: found changelog file: ${CHANGELOG}"; break; fi
             done
-            if [ ! -z "${CHANGELOG}" ]; then
+            if [ -n "${CHANGELOG}" ]; then
                 SEARCH=$(sed 's/^## //' ${CHANGELOG} | grep -E "^${PROGRAM_NAME} ${SEARCH_VERSION}")
                 if [ $? -eq 0 ]; then
                     while read -r LINE; do
@@ -358,7 +358,7 @@ if [ $# -gt 0 ]; then
                 VALUE=$(echo ${LINE} | awk -F';' '{print $2}')
                 DESCRIPTION=$(echo ${LINE} | awk -F';' '{print $3}' | sed 's/:space:/ /g')
                 if [ -z "${VALUE}" -a ${CONFIGURED_ONLY_OUTPUT} -eq 0 ]; then VALUE="${GRAY}[not configured]${NORMAL}"; fi
-                if [ ! -z "${VALUE}" ]; then
+                if [ -n "${VALUE}" ]; then
                     if [ ${BRIEF_OUTPUT} -eq 0 ]; then ${ECHOCMD} "${GRAY}# ${DESCRIPTION}${NORMAL}"; fi
                     ${ECHOCMD} "${WHITE}${SETTING}${NORMAL}=${CYAN}${VALUE}${NORMAL}"
                     if [ ${BRIEF_OUTPUT} -eq 0 ]; then ${ECHOCMD} ""; fi
diff --git a/include/osdetection b/include/osdetection
index a6c18bb5..95f2e014 100644
--- a/include/osdetection
+++ b/include/osdetection
@@ -139,7 +139,7 @@
             # Generic
             if [ -e /etc/os-release ]; then
                 OS_ID=$(grep "^ID=" /etc/os-release | awk -F= '{print $2}' | tr -d '"')
-                if [ ! -z "${OS_ID}" ]; then
+                if [ -n "${OS_ID}" ]; then
                     case ${OS_ID} in
                         "arch")
                             LINUX_VERSION="Arch Linux"
@@ -513,14 +513,14 @@
     EOL=255
     EOL_DATE=""
     EOL_TIMESTAMP=0
-    if [ ! -z "${OS_VERSION}" ]; then
+    if [ -n "${OS_VERSION}" ]; then
         if [ -f "${DBDIR}/software-eol.db" ]; then
             FIND="${OS_FULLNAME}"
             EOL_TIMESTAMP=$(awk -v value="${FIND}" -F: '{if ($1=="os" && value ~ $2){print $4}}' ${DBDIR}/software-eol.db | head -n 1)
-            if [ ! -z "${EOL_TIMESTAMP}" ]; then
+            if [ -n "${EOL_TIMESTAMP}" ]; then
                 EOL_DATE=$(awk -v value="${FIND}" -F: '{if ($1=="os" && value ~ $2){print $3}}' ${DBDIR}/software-eol.db | head -n 1)
                 NOW=$(date "+%s")
-                if [ ! -z "${NOW}" ]; then
+                if [ -n "${NOW}" ]; then
                     if [ ${NOW} -gt ${EOL_TIMESTAMP} ]; then
                         EOL=1
                     else
diff --git a/include/profiles b/include/profiles
index ad5e6b07..e27c84cd 100644
--- a/include/profiles
+++ b/include/profiles
@@ -77,7 +77,7 @@
                 # Is Lynis Enterprise allowed to purge this system when it is becomes outdated?
                 allow-auto-purge)
                     FIND=$(echo "${VALUE}" | egrep "^(1|true|yes)$")
-                    if [ ! -z "${FIND}" ]; then
+                    if [ -n "${FIND}" ]; then
                         Report "allow-auto-purge=1"
                     else
                         Report "allow-auto-purge=0"
@@ -110,7 +110,7 @@
                     # Quick mode (SKIP_PLUGINS) might already be set outside profile, so store in different variable
                     SETTING_COLORS=1 # default is yes
                     FIND=$(echo "${VALUE}" | egrep "^(0|false|no)$") && COLORS=0
-                    if [ ! -z "${FIND}" ]; then SETTING_COLORS=0; RemoveColors; fi
+                    if [ -n "${FIND}" ]; then SETTING_COLORS=0; RemoveColors; fi
                     Debug "Colors set to ${SETTING_COLORS}"
                     AddSetting "colors" "${SETTING_COLORS}" "Colored screen output"
                     unset SETTING_COLORS
@@ -204,7 +204,7 @@
                 ;;
 
                 hostalias | host-alias)
-                    if [ ! -z "${VALUE}" ]; then Report "hostname_alias=${VALUE}"; fi
+                    if [ -n "${VALUE}" ]; then Report "hostname_alias=${VALUE}"; fi
                 ;;
 
                 hostid)
@@ -223,13 +223,13 @@
                 # Language
                 language | lang)
                     LogText "Language set via profile to '${VALUE}'"
-                    if [ ! -z "${VALUE}" ]; then LANGUAGE="${VALUE}"; fi
+                    if [ -n "${VALUE}" ]; then LANGUAGE="${VALUE}"; fi
                     AddSetting "language" "${LANGUAGE}" "Language"
                 ;;
 
                 # Lynis Enterprise license key
                 license-key | license_key)
-                    if [ ! -z "${VALUE}" ]; then
+                    if [ -n "${VALUE}" ]; then
                         LICENSE_KEY="${VALUE}"
                         Report "license_key=${VALUE}"
                     fi
@@ -291,7 +291,7 @@
                     # Quick mode might already be set outside profile, so store in different variable
                     SETTING_QUICK_MODE=1 # default is yes
                     FIND=$(echo "${VALUE}" | egrep "^(0|false|no)$") && QUICKMODE=0
-                    if [ ! -z "${FIND}" ]; then SETTING_QUICK_MODE=1; fi
+                    if [ -n "${FIND}" ]; then SETTING_QUICK_MODE=1; fi
                     Debug "Quickmode set to ${SETTING_QUICK_MODE}"
                     AddSetting "quick" "${SETTING_QUICK_MODE}" "Quick mode (non-interactive)"
                 ;;
@@ -300,7 +300,7 @@
                 refresh-repositories)
                     SETTING_REFRESH_REPOSITORIES=1 # default is yes
                     FIND=$(echo "${VALUE}" | egrep "^(0|false|no)$") && REFRESH_REPOSITORIES=0
-                    if [ ! -z "${FIND}" ]; then SETTING_REFRESH_REPOSITORIES=0; fi
+                    if [ -n "${FIND}" ]; then SETTING_REFRESH_REPOSITORIES=0; fi
                     Debug "Refreshing repositories set to ${SETTING_REFRESH_REPOSITORIES}"
                     AddSetting "refresh-repositories" "${SETTING_REFRESH_REPOSITORIES}" "Refresh repositories (for vulnerable package detection)"
                 ;;
@@ -309,7 +309,7 @@
                 show-report-solution)
                     SETTING_SHOW_REPORT_SOLUTION=${SHOW_REPORT_SOLUTION}
                     FIND=$(echo "${VALUE}" | egrep "^(0|false|no)$") && SHOW_REPORT_SOLUTION=0
-                    if [ ! -z "${FIND}" ]; then SETTING_SHOW_REPORT_SOLUTION=0; fi
+                    if [ -n "${FIND}" ]; then SETTING_SHOW_REPORT_SOLUTION=0; fi
                     Debug "Show report details (solution) set to ${SETTING_SHOW_REPORT_SOLUTION}"
                 ;;
 
@@ -317,7 +317,7 @@
                 show_tool_tips | show-tool-tips)
                     SETTING_SHOW_TOOL_TIPS=1 # default is yes
                     FIND=$(echo "${VALUE}" | egrep "^(0|false|no)$") && SHOW_TOOL_TIPS=0
-                    if [ ! -z "${FIND}" ]; then SETTING_SHOW_TOOL_TIPS=0; fi
+                    if [ -n "${FIND}" ]; then SETTING_SHOW_TOOL_TIPS=0; fi
                     Debug "Show tool tips set to ${SETTING_SHOW_TOOL_TIPS}"
                     AddSetting "show-tool-tips" "${SETTING_SHOW_TOOL_TIPS}" "Show tool tips"
                 ;;
@@ -336,7 +336,7 @@
                     # Skip plugins (SKIP_PLUGINS) might already be set, so store in different variable
                     SETTING_SKIP_PLUGINS=0 # default is no
                     FIND=$(echo "${VALUE}" | egrep "^(1|true|yes)$") && SKIP_PLUGINS=1
-                    if [ ! -z "${FIND}" ]; then SETTING_SKIP_PLUGINS=1; fi
+                    if [ -n "${FIND}" ]; then SETTING_SKIP_PLUGINS=1; fi
                     Debug "Skip plugins is set to ${SETTING_SKIP_PLUGINS}"
                     AddSetting "skip-plugins" "${SETTING_SKIP_PLUGINS}" "Skip plugins"
                 ;;
@@ -374,17 +374,17 @@
 
                 # The name of the customer/client that uses this system
                 system-customer-name)
-                    if [ ! -z "${VALUE}" ]; then Report "system-customer-name=${VALUE}"; fi
+                    if [ -n "${VALUE}" ]; then Report "system-customer-name=${VALUE}"; fi
                 ;;
 
                 # The groups linked to a system (system-groups=customers,webservers,production)
                 system-groups)
-                    if [ ! -z "${VALUE}" ]; then Report "system-groups=${VALUE}"; fi
+                    if [ -n "${VALUE}" ]; then Report "system-groups=${VALUE}"; fi
                 ;;
 
                 # Tags (tags=db,production,ssn-1304)
                 tags)
-                    if [ ! -z "${VALUE}" ]; then Report "tags=${VALUE}"; fi
+                    if [ -n "${VALUE}" ]; then Report "tags=${VALUE}"; fi
                 ;;
 
                 # Define what kind of scan we are performing
@@ -399,7 +399,7 @@
                 upload)
                     SETTING_UPLOAD=no # default
                     FIND=$(echo "${VALUE}" | egrep "^(1|true|yes)$") && UPLOAD_DATA=1
-                    if [ ! -z "${FIND}" ]; then SETTING_UPLOAD=1; fi
+                    if [ -n "${FIND}" ]; then SETTING_UPLOAD=1; fi
                     Debug "Upload set to ${SETTING_UPLOAD}"
                     AddSetting "upload" "${SETTING_UPLOAD}" "Data upload after scanning"
                     unset SETTING_UPLOAD
@@ -499,12 +499,12 @@
 #################################################################################
 #
     SKIP_TESTS=$(echo ${SKIP_TESTS} | sed "s/^ //")
-    if [ ! -z "${SKIP_TESTS}" ]; then LogText "Skip tests: ${SKIP_TESTS}"; fi
+    if [ -n "${SKIP_TESTS}" ]; then LogText "Skip tests: ${SKIP_TESTS}"; fi
 #
 #################################################################################
 #
     # Add group name to report - deprecated
-    if [ ! -z "${GROUP_NAME}" ]; then Report "group=${GROUP_NAME}"; fi
+    if [ -n "${GROUP_NAME}" ]; then Report "group=${GROUP_NAME}"; fi
 #
 #################################################################################
 #
@@ -531,7 +531,7 @@
 #
 #################################################################################
 #
-    if [ ! -z "${DEPRECATED_OPTION}" ]; then
+    if [ -n "${DEPRECATED_OPTION}" ]; then
         ReportWarning "LYNIS" "One or more deprecated options used" "${DEPRECATED_OPTION}" "Update your profile"
     fi
 #
diff --git a/include/report b/include/report
index 88d75ce0..c340da53 100644
--- a/include/report
+++ b/include/report
@@ -31,7 +31,7 @@
     Report "firewall_empty_ruleset=${FIREWALL_EMPTY_RULESET}"
     Report "firewall_installed=${FIREWALL_ACTIVE}"
 
-    if [ ! -z "${INSTALLED_PACKAGES}" ]; then Report "installed_packages_array=${INSTALLED_PACKAGES}"; fi
+    if [ -n "${INSTALLED_PACKAGES}" ]; then Report "installed_packages_array=${INSTALLED_PACKAGES}"; fi
 
     Report "package_audit_tool=${PACKAGE_AUDIT_TOOL}"
     Report "package_audit_tool_found=${PACKAGE_AUDIT_TOOL_FOUND}"
@@ -139,7 +139,7 @@
                     done
                     IS_CUSTOM=$(echo ${ADDLINK} | grep "^CUST")
                     echo "  ${RED}!${NORMAL} ${SHOWWARNING}"
-                    if [ ! "${DETAILS}" = "-" -a ! -z "${DETAILS}" ]; then echo "    - Details  : ${CYAN}${DETAILS}${NORMAL}"; fi
+                    if [ ! "${DETAILS}" = "-" -a -n "${DETAILS}" ]; then echo "    - Details  : ${CYAN}${DETAILS}${NORMAL}"; fi
                     if [ ${SHOW_REPORT_SOLUTION} -eq 1 -a ! "${SOLUTION}" = "-" ]; then echo "    - Solution : ${SOLUTION}"; fi
                     if [ -z "${IS_CUSTOM}" ]; then
                         echo "      ${CONTROL_URL_PROTOCOL}://${CONTROL_URL_PREPEND}${ADDLINK}${CONTROL_URL_APPEND}"
@@ -172,7 +172,7 @@
                     done
                     IS_CUSTOM=$(echo ${ADDLINK} | grep "^CUST")
                     echo "  ${YELLOW}*${NORMAL} ${SHOWSUGGESTION}"
-                    if [ ! "${DETAILS}" = "-" -a ! -z "${DETAILS}" ]; then echo "    - Details  : ${CYAN}${DETAILS}${NORMAL}"; fi
+                    if [ ! "${DETAILS}" = "-" -a -n "${DETAILS}" ]; then echo "    - Details  : ${CYAN}${DETAILS}${NORMAL}"; fi
                     if [ ${SHOW_REPORT_SOLUTION} -eq 1 -a ! "${SOLUTION}" = "-" ]; then echo "    - Solution : ${SOLUTION}"; fi
                     if [ -z "${IS_CUSTOM}" ]; then
                         echo "      ${GRAY}${CONTROL_URL_PROTOCOL}://${CONTROL_URL_PREPEND}${ADDLINK}${CONTROL_URL_APPEND}${NORMAL}"
diff --git a/include/tests_accounting b/include/tests_accounting
index 827f412a..2b2ceb46 100644
--- a/include/tests_accounting
+++ b/include/tests_accounting
@@ -105,7 +105,7 @@
         if [ -f ${ROOTDIR}etc/default/sysstat ]; then
             LogText "Result: ${ROOTDIR}etc/default/sysstat found"
             FIND=$(${GREPBINARY} "^ENABLED" ${ROOTDIR}etc/default/sysstat | ${GREPBINARY} -i true)
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 LogText "Result: sysstat enabled via ${ROOTDIR}etc/default/sysstat"
                 Display --indent 2 --text "- Checking sysstat accounting data" --result "${STATUS_ENABLED}" --color GREEN
             else
@@ -115,7 +115,7 @@
             fi
         elif [ -f ${ROOTDIR}etc/cron.d/sysstat ]; then
             FIND=$(${GREPBINARY} -v '^[[:space:]]*\(#\|$\)' ${ROOTDIR}etc/cron.d/sysstat)
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 LogText "Result: sysstat enabled via ${ROOTDIR}etc/cron.d/sysstat"
                 Display --indent 2 --text "- Checking sysstat accounting data" --result "${STATUS_ENABLED}" --color GREEN
             else
@@ -134,7 +134,7 @@
 #
     # Test        : ACCT-9628
     # Description : Check auditd status
-    if [ ! -z "${AUDITDBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${AUDITDBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no ACCT-9628 --os Linux --weight L --network NO --category security --description "Check for auditd"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Check auditd status"
@@ -163,7 +163,7 @@
 #
     # Test        : ACCT-9630
     # Description : Check auditd rules
-    if [ ! -z "${AUDITDBINARY}" -a ! -z "${AUDITCTLBINARY}" -a ${LINUX_AUDITD_RUNNING} -eq 1 ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${AUDITDBINARY}" -a -n "${AUDITCTLBINARY}" -a ${LINUX_AUDITD_RUNNING} -eq 1 ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no ACCT-9630 --os Linux --preqs-met ${PREQS_MET} --weight L --network NO --root-only YES --category security --description "Check for auditd rules"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking auditd rules"
@@ -189,7 +189,7 @@
 #
     # Test        : ACCT-9632
     # Description : Check auditd configuration file
-    if [ ! -z "${AUDITDBINARY}" -a ${LINUX_AUDITD_RUNNING} -eq 1 ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${AUDITDBINARY}" -a ${LINUX_AUDITD_RUNNING} -eq 1 ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no ACCT-9632 --os Linux --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check for auditd configuration file"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking auditd configuration file"
@@ -202,7 +202,7 @@
             fi
         done
         # Check if we discovered the configuration file. It should be there is the binaries are available and process is running
-        if [ ! -z "${AUDITD_CONF_FILE}" ]; then
+        if [ -n "${AUDITD_CONF_FILE}" ]; then
             Display --indent 4 --text "- Checking audit configuration file" --result "${STATUS_OK}" --color GREEN
         else
             LogText "Result: could not find auditd configuration file"
@@ -215,12 +215,12 @@
 #
     # Test        : ACCT-9634
     # Description : Check auditd log file
-    if [ ! -z "${AUDITDBINARY}" -a ${LINUX_AUDITD_RUNNING} -eq 1 -a ! -z "${AUDITD_CONF_FILE}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${AUDITDBINARY}" -a ${LINUX_AUDITD_RUNNING} -eq 1 -a -n "${AUDITD_CONF_FILE}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no ACCT-9634 --os Linux --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check for auditd log file"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking auditd log file"
         FIND=$(${GREPBINARY} "^log_file" ${AUDITD_CONF_FILE} | ${AWKBINARY} '{ if ($1=="log_file" && $2=="=") { print $3 } }')
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             LogText "Result: log file is defined"
             LogText "Defined value: ${FIND}"
             if [ -f ${FIND} ]; then
@@ -252,7 +252,7 @@
             if [ -f ${ROOTDIR}etc/ld.so.preload ]; then
                 LogText "Result: found ${ROOTDIR}etc/ld.so.preload, testing if snoopy.so is listed"
                 FIND=$(${GREPBINARY} ${FILE} ${ROOTDIR}etc/ld.so.preload)
-                if [ ! -z "${FIND}" ]; then
+                if [ -n "${FIND}" ]; then
                     LogText "Result: found snoopy in ld.so.preload"
                     LogText "Output: ${FIND}"
                     Display --indent 6 --text "- Library in ld.so.preload" --result "LOADED" --color GREEN
@@ -298,7 +298,7 @@
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: check if auditd service is enabled and online"
         FIND=$(${ROOTDIR}usr/bin/svcs svc:/system/auditd:default | ${GREPBINARY} "^online")
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             LogText "Result: auditd service is online"
             Display --indent 4 --text "- Checking Solaris audit daemon status" --result "${STATUS_ON}"LINE --color GREEN
         else
@@ -317,7 +317,7 @@
         LogText "Test: check if BSM is enabled in ${ROOTDIR}etc/system"
         if [ -f ${ROOTDIR}etc/system ]; then
             FIND=$(${GREPBINARY} 'set c2audit:audit_load = 1' ${ROOTDIR}etc/system)
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 LogText "Result: BSM is enabled in ${ROOTDIR}etc/system"
                 Display --indent 4 --text "- Checking Solaris BSM (${ROOTDIR}etc/system)" --result "${STATUS_ENABLED}" --color GREEN
             else
@@ -339,7 +339,7 @@
         LogText "Test: check if c2audit module is active"
         if [ -x ${ROOTDIR}usr/sbin/modinfo ]; then
             FIND=$(${ROOTDIR}usr/sbin/modinfo | ${GREPBINARY} c2audit)
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 LogText "Result: c2audit found in modinfo output"
                 Display --indent 4 --text "- Checking Solaris BSM (modules list)" --result "${STATUS_ENABLED}" --color GREEN
             else
@@ -362,7 +362,7 @@
         if [ -f ${ROOTDIR}etc/security/audit_control ]; then
             LogText "Result: file ${ROOTDIR}etc/security/audit_control found"
             FIND=$(${GREPBINARY} "^dir" ${ROOTDIR}etc/security/audit_control | ${AWKBINARY} -F: '{ print $2 }')
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 LogText "Result: found location ${FIND}"
                 LogText "Test: Checking if location is a valid directory"
                 if [ -d ${FIND} ]; then
diff --git a/include/tests_authentication b/include/tests_authentication
index 6c867da6..c931ab77 100644
--- a/include/tests_authentication
+++ b/include/tests_authentication
@@ -46,7 +46,7 @@
         else
             FIND=$(${GREPBINARY} ':0:' ${ROOTDIR}etc/passwd | ${EGREPBINARY} -v '^#|^root:|^(\+:\*)?:0:0:::' | ${CUTBINARY} -d ":" -f1,3 | ${GREPBINARY} ':0')
         fi
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             Display --indent 2 --text "- Administrator accounts" --result "${STATUS_WARNING}" --color RED
             LogText "Result: Found more than one administrator accounts"
             ReportWarning "${TEST_NO}" "Multiple users with UID 0 found in passwd file"
@@ -124,7 +124,7 @@
     # Test        : AUTH-9216
     # Description : Check /etc/group and shadow group files
     # Notes       : Run grpck to test group files (most likely /etc/group and shadow group files)
-    if [ ! -z "${GRPCKBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${GRPCKBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no AUTH-9216 --preqs-met ${PREQS_MET} --weight L --network NO --root-only YES --category security --description "Check group and shadow group files"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking for grpck binary output"
@@ -363,7 +363,7 @@
             "macOS")
                 LogText "macOS real users output (ID = 0, or 500-599) using dscacheutil"
                 FIND_USERS=$(dscacheutil -q user | ${GREPBINARY} -A 3 -B 2 -e "^uid: 5[0-9][0-9]" | ${GREPBINARY} "^name: " | ${AWKBINARY} '{print $2}')
-                if [ ! -z "${FIND_USERS}" ]; then
+                if [ -n "${FIND_USERS}" ]; then
                     for FUSERNAME in ${FIND_USERS}; do
                         FDETAILS=$(dscacheutil -q user -a name ${FUSERNAME} | ${GREPBINARY} "^uid: " | ${AWKBINARY} '{print $2}')
                         FIND="${FUSERNAME},${FDETAILS} ${FIND}"
@@ -397,7 +397,7 @@
         else
             Display --indent 2 --text "- Query system users (non daemons)" --result "${STATUS_DONE}" --color GREEN
             for I in ${FIND}; do
-                if [ ! -z "${I}" ]; then
+                if [ -n "${I}" ]; then
                     LogText "Real user: ${I}"
                     Report "real_user[]=${I}"
                 fi
@@ -419,7 +419,7 @@
             else
                 FIND2=$(${EGREPBINARY} "^passwd_compat" ${ROOTDIR}etc/nsswitch.conf | ${GREPBINARY} "nisplus")
                 FIND3=$(${EGREPBINARY} "^passwd" ${ROOTDIR}etc/nsswitch.conf | ${GREPBINARY} "nisplus")
-                if [ ! -z "${FIND2}" -o ! -z "${FIND3}" ]; then
+                if [ -n "${FIND2}" -o -n "${FIND3}" ]; then
                     LogText "Result: NIS+ authentication enabled"
                     Display --indent 2 --text "- NIS+ authentication support" --result "${STATUS_ENABLED}" --color GREEN
                 else
@@ -446,7 +446,7 @@
             else
                 FIND2=$(${EGREPBINARY} "^passwd_compat" /etc/nsswitch.conf | ${GREPBINARY} "nis" | ${GREPBINARY} -v "nisplus")
                 FIND3=$(${EGREPBINARY} "^passwd" /etc/nsswitch.conf | ${GREPBINARY} "nis" | ${GREPBINARY} -v "nisplus")
-                if [ ! -z "${FIND2}" -o ! -z "${FIND3}" ]; then
+                if [ -n "${FIND2}" -o -n "${FIND3}" ]; then
                     LogText "Result: NIS authentication enabled"
                     Display --indent 2 --text "- NIS authentication support" --result "${STATUS_ENABLED}" --color GREEN
                 else
@@ -489,7 +489,7 @@
 #
     # Test        : AUTH-9252
     # Description : Check ownership and permissions for sudo configuration files
-    if [ ! -z "${SUDOERS_FILE}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${SUDOERS_FILE}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no AUTH-9252 --preqs-met ${PREQS_MET} --weight L --network NO --root-only YES --category security --description "Check ownership and permissions for sudo configuration files"
     if [ ${SKIPTEST} -eq 0 ]; then
         SUDO_CONFIG_FILES="${SUDOERS_FILE}"
@@ -680,7 +680,7 @@
                 else
                     FIND=$(find ${DIR} -maxdepth 1 -type f -name "pam_*.so" -print | sort)
                 fi
-                if [ ! -z "${FIND}" ]; then FOUND=1; fi
+                if [ -n "${FIND}" ]; then FOUND=1; fi
                 for FILE in ${FIND}; do
                     LogText "Found file: ${FILE}"
                     Report "pam_module[]=${FILE}"
@@ -712,7 +712,7 @@
                 LogText "Result: file ${FILE} exists"
                 LogText "Test: checking presence LDAP module"
                 FIND=$(${GREPBINARY} "^auth.*ldap" ${FILE})
-                if [ ! -z "${FIND}" ]; then
+                if [ -n "${FIND}" ]; then
                     LogText "Result: LDAP module present"
                     LogText "Output: ${FIND}"
                     LDAP_AUTH_ENABLED=1
@@ -868,7 +868,7 @@
             LogText "Test: collecting accounts which have an expired password (last day changed + maximum change time)"
             # Skip fields with a !, *, or x, or !* (field $3 is last changed, $5 is maximum changed)
             FIND=$(${EGREPBINARY} -v ":[\!\*x]([\*\!])?:" /etc/shadow | ${AWKBINARY} -v today=${DAYS_SINCE_EPOCH} -F: '{ if (($5!="") && (today>$3+$5)) { print $1 }}')
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 for ACCOUNT in ${FIND}; do
                     LogText "Result: password of user ${ACCOUNT} has been expired"
                     Report "account_password_expired[]=${ACCOUNT}"
@@ -961,7 +961,7 @@
                 LogText "Test: checking presence sulogin for single user mode"
                 FIND=$(${EGREPBINARY} "^[a-zA-Z0-9~]+:S:(respawn|wait):/sbin/sulogin" /etc/inittab)
                 FIND2=$(${EGREPBINARY} "^su:S:(respawn|wait):/sbin/sulogin" /etc/inittab)
-                if [ ! -z "${FIND}" -o ! -z "${FIND2}" ]; then
+                if [ -n "${FIND}" -o -n "${FIND2}" ]; then
                     FOUND=1
                     LogText "Result: found sulogin, so single user is protected"
                 fi
@@ -976,7 +976,7 @@
                 LogText "Result: file ${ROOTDIR}etc/sysconfig/init exists"
                 LogText "Test: checking presence sulogin for single user mode"
                 FIND=$(${GREPBINARY} "^SINGLE=/sbin/sulogin" ${ROOTDIR}etc/sysconfig/init)
-                if [ ! -z "${FIND}" ]; then
+                if [ -n "${FIND}" ]; then
                     FOUND=1
                     LogText "Result: found sulogin, so single user is protected"
                 fi
@@ -1045,7 +1045,7 @@
         if [ -d ${ROOTDIR}etc/profile.d ]; then
             FOUND=0
             FIND=$(ls ${ROOTDIR}etc/profile.d/* 2> /dev/null)
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 LogText "Result: found /etc/profile.d, with one or more files in it"
                 for FILE in ${FIND}; do
                     HAS_MASK=$(${GREPBINARY} umask ${FILE} | ${SEDBINARY} 's/^[ \t]*//' | ${GREPBINARY} -v "^#" | ${AWKBINARY} '{ print $2 }')
@@ -1309,7 +1309,7 @@
             if [ -f ${ROOTDIR}etc/default/login ]; then
                 LogText "Result: file ${ROOTDIR}etc/default/login exists"
                 FIND=$(${GREPBINARY} "^RETRIES" ${ROOTDIR}etc/default/login)
-                if [ ! -z "${FIND}" ]; then
+                if [ -n "${FIND}" ]; then
                     FOUND=1
                     LogText "Result: retries option configured"
                     LogText "Output: ${FIND}"
@@ -1429,7 +1429,7 @@
 #
     # Test        : AUTH-9410
     # Description : Check for doas file permissions
-    if [ ! -z "${DOAS_FILE}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${DOAS_FILE}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no AUTH-9410 --os OpenBSD --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check /etc/doas.conf file permissions"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: checking /etc/doas.conf permissions"
@@ -1450,7 +1450,7 @@
 Report "auth_failed_logins_logged=${AUTH_FAILED_LOGINS_LOGGED}"
 Report "ldap_auth_enabled=${LDAP_AUTH_ENABLED}"
 Report "ldap_pam_enabled=${LDAP_PAM_ENABLED}"
-if [ ! -z "${LDAP_CLIENT_CONFIG_FILE}" ]; then Report "ldap_config_file=${LDAP_CLIENT_CONFIG_FILE}"; fi
+if [ -n "${LDAP_CLIENT_CONFIG_FILE}" ]; then Report "ldap_config_file=${LDAP_CLIENT_CONFIG_FILE}"; fi
 Report "password_min_days=${PASSWORD_MINIMUM_DAYS}"
 Report "password_max_days=${PASSWORD_MAXIMUM_DAYS}"
 
diff --git a/include/tests_boot_services b/include/tests_boot_services
index 42b8dab1..2fee353f 100644
--- a/include/tests_boot_services
+++ b/include/tests_boot_services
@@ -46,7 +46,7 @@
         LogText "Test: Query bootinfo for AIX boot device"
         if [ -x /usr/sbin/bootinfo ]; then
             FIND=$(/usr/sbin/bootinfo -b)
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 LogText "Result: found boot device ${FIND}"
                 Display --indent 2 --text "- Checking boot device (bootinfo)" --result "${STATUS_FOUND}" --color GREEN
                 BOOT_LOADER="ROS"
@@ -76,7 +76,7 @@
                     FILENAME=$(echo "${OUTPUT}" | ${AWKBINARY} '{print $1}')
                     LogText "Result: file on disk = ${FILENAME}"
                     ISFILE=$(echo ${FILENAME} | ${GREPBINARY} "^/")
-                    if [ ! -z "${ISFILE}" ]; then
+                    if [ -n "${ISFILE}" ]; then
                         if [ -L ${ISFILE} ]; then
                             ShowSymlinkPath ${ISFILE}
                             FILENAME="${SYMLINK}"
@@ -86,7 +86,7 @@
                             LogText "Result: cmdline of PID 1 is not a file"
                         fi
                     fi
-                    if [ ! -z "${FILENAME}" ]; then
+                    if [ -n "${FILENAME}" ]; then
                         SHORTNAME=$(echo ${FILENAME} | ${AWKBINARY} -F/ '{ print $NF }')
                         LogText "Found: ${SHORTNAME}"
                         if [ "${SERVICE_MANAGER}" = "unknown" ]; then
@@ -110,7 +110,7 @@
                                 ;;
                                 *)
                                     CONTAINS_SYSTEMD=$(echo ${SHORTNAME} | ${GREPBINARY} "systemd")
-                                    if [ ! -z "${CONTAINS_SYSTEMD}" ]; then
+                                    if [ -n "${CONTAINS_SYSTEMD}" ]; then
                                         SERVICE_MANAGER="systemd"
                                     else
                                         LogText "Found ${SHORTNAME}. Unclear what service manager this is"
@@ -204,7 +204,7 @@
                 LogText "Test: determine if Secure Boot is used"
                 if [ -d ${ROOTDIR}sys/firmware/efi/efivars ]; then
                     FIND=$(${LSBINARY} ${ROOTDIR}sys/firmware/efi/efivars/SecureBoot-* 2> /dev/null)
-                    if [ ! -z "${FIND}" ]; then
+                    if [ -n "${FIND}" ]; then
                         for FILE in ${FIND}; do
                             LogText "Test: checking file ${FILE}"
                             # TODO: add detection for od
@@ -295,7 +295,7 @@
         # Some OSes like Gentoo do not have /boot mounted by default
         # TODO: root directory and rewrite ls statement
         if [ -d /boot ]; then
-            if [ "$(ls /boot/* 2> /dev/null)" = "" -a ! -z "${GRUB2INSTALLBINARY}" ]; then
+            if [ "$(ls /boot/* 2> /dev/null)" = "" -a -n "${GRUB2INSTALLBINARY}" ]; then
                 BOOT_LOADER_FOUND=1
                 LogText "Result: found empty /boot, however with GRUB2 binary installed. Best guess is that GRUB2 is actually installed, but /boot not mounted"
                 Display --indent 2 --text "- Checking presence GRUB2" --result "POSSIBLE MATCH" --color YELLOW
@@ -312,7 +312,7 @@
 #
     # Test        : BOOT-5122
     # Description : Check for GRUB boot loader configuration
-    if [ ! -z "${GRUBCONFFILE}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${GRUBCONFFILE}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no BOOT-5122 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check for GRUB boot password"
     if [ ${SKIPTEST} -eq 0 ]; then
         FOUND=0
@@ -325,11 +325,11 @@
             FIND4=$(${GREPBINARY} 'password_pbkdf2' ${GRUBCONFFILE} | ${GREPBINARY} -v '^#')
             FIND5=$(${GREPBINARY} 'grub.pbkdf2' ${GRUBCONFFILE} | ${GREPBINARY} -v '^#')
             # GRUB1: Password should be set (MD5 or SHA1)
-            if [ ! -z "${FIND}" -o ! -z "${FIND2}" ]; then
+            if [ -n "${FIND}" -o -n "${FIND2}" ]; then
                 FOUND=1
             # GRUB2: Superusers AND password should be defined
-            elif [ ! -z "${FIND3}" ]; then
-                if [ ! -z "${FIND4}" -o ! -z "${FIND5}" ]; then FOUND=1; fi
+            elif [ -n "${FIND3}" ]; then
+                if [ -n "${FIND4}" -o -n "${FIND5}" ]; then FOUND=1; fi
             fi
             if [ ${FOUND} -eq 1 ]; then
                 Display --indent 4 --text "- Checking for password protection" --result "${STATUS_OK}" --color GREEN
@@ -599,7 +599,7 @@
         else
 
             LogText "Result: systemctl binary not found, checking chkconfig binary"
-            if [ ! -z "${CHKCONFIGBINARY}" ]; then
+            if [ -n "${CHKCONFIGBINARY}" ]; then
                 LogText "Result: chkconfig binary found, trying that to discover information"
                 LogText "Searching for services at startup (chkconfig, runlevel 3 and 5)"
                 FIND=$(${CHKCONFIGBINARY} --list | ${EGREPBINARY} '3:on|5:on' | ${AWKBINARY} '{ print $1 }')
@@ -634,7 +634,7 @@
         if [ "${sRUNLEVEL}" = "2" ]; then
             LogText "Result: performing find in /etc/rc2.d as runlevel 2 is found"
             FIND=$(${FINDBINARY} ${ROOTDIR}etc/rc2.d -type l -print | ${CUTBINARY} -d '/' -f4 | ${SEDBINARY} "s/S[0-9][0-9]//g" | sort)
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 COUNT=0
                 for SERVICE in ${FIND}; do
                     LogText "Found service (at boot, runlevel 2): ${SERVICE}"
@@ -667,7 +667,7 @@
                 LogText "Result: directory ${DIR} found"
                 LogText "Test: checking for available files in directory"
                 FIND=$(${FINDBINARY} ${DIR} -type f -print | ${SORTBINARY})
-                if [ ! -z "${FIND}" ]; then
+                if [ -n "${FIND}" ]; then
                     LogText "Result: found files in directory, checking permissions now"
                     for FILE in ${FIND}; do
                         LogText "Test: checking permissions of file ${FILE}"
@@ -757,12 +757,12 @@
                 ;;
 
              DragonFly | FreeBSD | macOS)
-                if [ ! -z "${SYSCTLBINARY}" ]; then
+                if [ -n "${SYSCTLBINARY}" ]; then
                     TIME_BOOT=$(${SYSCTLBINARY} kern.boottime | ${AWKBINARY} '{ print $5 }' | ${SEDBINARY} -e 's/,//' | ${GREPBINARY} "[0-9]")
                     TIME_NOW=$(date "+%s")
                     LogText "Boot time: ${TIME_BOOT}"
                     LogText "Current time: ${TIME_NOW}"
-                    if [ ! -z "${TIME_BOOT}" -a ! -z "${TIME_NOW}" ]; then
+                    if [ -n "${TIME_BOOT}" -a -n "${TIME_NOW}" ]; then
                         UPTIME_IN_SECS=$((TIME_NOW - TIME_BOOT))
                     else
                         ReportException "${TEST_NO}:5" "Most likely kern.boottime empty, unable to determine uptime"
@@ -774,12 +774,12 @@
                 ;;
 
              NetBSD | OpenBSD)
-                if [ ! -z "${SYSCTLBINARY}" ]; then
+                if [ -n "${SYSCTLBINARY}" ]; then
                     TIME_BOOT=$(${SYSCTLBINARY} -n kern.boottime)
                     TIME_NOW=$(date "+%s")
                     LogText "Boot time: ${TIME_BOOT}"
                     LogText "Current time: ${TIME_NOW}"
-                    if [ ! -z "${TIME_BOOT}" -a ! -z "${TIME_NOW}" ]; then
+                    if [ -n "${TIME_BOOT}" -a -n "${TIME_NOW}" ]; then
                         UPTIME_IN_SECS=$((TIME_NOW - TIME_BOOT))
                     else
                         ReportException "${TEST_NO}:5" "Most likely kern.boottime empty, unable to determine uptime"
@@ -791,7 +791,7 @@
                 ;;
 
             Solaris)
-                if [ ! -z "${KSTATBINARY}" ]; then
+                if [ -n "${KSTATBINARY}" ]; then
                     UPTIME_IN_SECS=$(${KSTATBINARY} -p unix:0:system_misc:snaptime | ${GREPBINARY} "^unix" | ${AWKBINARY} '{print $2}' | ${CUTBINARY} -d "." -f1)
                 else
                     Display --indent 2 --text "- Checking uptime" --result "${STATUS_SKIPPED}" --color YELLOW
@@ -806,7 +806,7 @@
                 ReportException "${TEST_NO}:3" "No uptime test available yet for this operating system"
                 ;;
         esac
-        if [ ! -z "${UPTIME_IN_SECS}" ]; then
+        if [ -n "${UPTIME_IN_SECS}" ]; then
             UPTIME_IN_DAYS=$((UPTIME_IN_SECS / 60 / 60 / 24))
             LogText "Uptime (in seconds): ${UPTIME_IN_SECS}"
             LogText "Uptime (in days): ${UPTIME_IN_DAYS}"
@@ -828,7 +828,7 @@
             LogText "Result: file /usr/lib/systemd/system/rescue.service"
             LogText "Test: checking presence sulogin for single user mode"
             FIND=$(${EGREPBINARY} "^ExecStart=.*sulogin" ${ROOTDIR}usr/lib/systemd/system/rescue.service)
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 FOUND=1
                 LogText "Result: found sulogin, so single user is protected"
                 AddHP 3 3
@@ -898,7 +898,7 @@
             LogText "Test: checking for available files in directory"
             # OpenBSD uses symlinks to create another instance of daemons
             FIND=$(${FINDBINARY} ${CHECKDIR} \( -type f -o -type l \) -print | ${SORTBINARY})
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 LogText "Result: found files in directory, checking permissions now"
                 for FILE in ${FIND}; do
                     LogText "Test: checking permissions of file ${FILE}"
diff --git a/include/tests_containers b/include/tests_containers
index 97351d92..4d722e52 100644
--- a/include/tests_containers
+++ b/include/tests_containers
@@ -40,7 +40,7 @@
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: query zoneadm to list all running zones"
         FIND=$(${ROOTDIR}usr/sbin/zoneadm list -p | ${AWKBINARY} -F: '{ if ($2!="global") print $0 }')
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             COUNT=0
             for ITEM in ${FIND}; do
                 COUNT=$((COUNT + 1))
@@ -131,7 +131,7 @@
     # Test        : CONT-8106
     # Description : Checking Docker containers (basic stats)
     # Notes       : Hardening points are awarded, if there aren't a lot of stopped containers
-    if [ ! -z "${DOCKERBINARY}" -a ${RUN_DOCKER_TESTS} -eq 1 ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${DOCKERBINARY}" -a ${RUN_DOCKER_TESTS} -eq 1 ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no CONT-8106 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Gather basic stats from Docker"
     if [ ${SKIPTEST} -eq 0 ]; then
         Display --indent 6 --text "- Containers"
@@ -171,7 +171,7 @@
     # Test        : CONT-8107
     # Description : Checking Docker number of unused containers
     # Notes       : Hardening points are awarded, if there aren't a lot of stopped containers
-    if [ ! -z "${DOCKERBINARY}" -a ${RUN_DOCKER_TESTS} -eq 1 ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${DOCKERBINARY}" -a ${RUN_DOCKER_TESTS} -eq 1 ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no CONT-8107 --preqs-met ${PREQS_MET} --weight L --network NO --category performance --description "Check number of Docker containers"
     if [ ${SKIPTEST} -eq 0 ]; then
         # Check if there aren't too many unused containers on the system
@@ -194,7 +194,7 @@
     # Test        : CONT-8108
     # Description : Checking Docker file permissions
     # Notes       : /var/run/docker.sock - Usually root as owner, docker as group - should not be world writable
-    if [ ! -z "${DOCKERBINARY}" -a ${RUN_DOCKER_TESTS} -eq 1 ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${DOCKERBINARY}" -a ${RUN_DOCKER_TESTS} -eq 1 ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no CONT-8108 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check file permissions for Docker files"
     if [ ${SKIPTEST} -eq 0 ]; then
         NOT_WORLD_WRITABLE="${ROOTDIR}var/run/docker.sock"
diff --git a/include/tests_crypto b/include/tests_crypto
index 6d0d5384..ecb19d2f 100644
--- a/include/tests_crypto
+++ b/include/tests_crypto
@@ -28,7 +28,7 @@
 #
     # Test        : CRYP-7902
     # Description : check for expired SSL certificates
-    if [ ! -z "${OPENSSLBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${OPENSSLBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no CRYP-7902 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check expire date of SSL certificates"
     if [ ${SKIPTEST} -eq 0 ]; then
         COUNT_EXPIRED=0
diff --git a/include/tests_databases b/include/tests_databases
index d3bd2777..43d0d025 100644
--- a/include/tests_databases
+++ b/include/tests_databases
@@ -71,7 +71,7 @@
     # Test        : DBS-1816
     # Description : Check empty MySQL root password
     # Notes       : Only perform test when MySQL is running and client is available
-    if [ ! -z "${MYSQLCLIENTBINARY}" -a ${MYSQL_RUNNING} -eq 1 ]; then PREQS_MET="YES"; SKIPREASON=""; else PREQS_MET="NO"; SKIPREASON="MySQL not installed, or not running"; fi
+    if [ -n "${MYSQLCLIENTBINARY}" -a ${MYSQL_RUNNING} -eq 1 ]; then PREQS_MET="YES"; SKIPREASON=""; else PREQS_MET="NO"; SKIPREASON="MySQL not installed, or not running"; fi
     Register --test-no DBS-1816 --preqs-met ${PREQS_MET} --skip-reason "${SKIPREASON}" --weight L --network NO --category security --description "Checking MySQL root password"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Trying to login to local MySQL server without password"
@@ -144,7 +144,7 @@
             if [ ${MONGODB_AUTHORIZATION_ENABLED} -eq 0 ]; then
                 if HasData "${PGREPBINARY}"; then
                     AUTH_ON_CMDLINE=$(for I in $(${PGREPBINARY} mongo); do cat /proc/${I}/cmdline | xargs -0 echo | ${GREPBINARY} -E "\-\-auth( |$)"; done)
-                    if [ ! -z "${AUTH_ON_CMDLINE}" ]; then LogText "Result: found authorization enabled via mongod parameter"; MONGODB_AUTHORIZATION_ENABLED=1; fi
+                    if [ -n "${AUTH_ON_CMDLINE}" ]; then LogText "Result: found authorization enabled via mongod parameter"; MONGODB_AUTHORIZATION_ENABLED=1; fi
                 else
                     LogText "Result: skipped this part of the test, as pgrep is not available"
                 fi
@@ -268,7 +268,7 @@
         for DIR in ${PATHS}; do
             LogText "Action: scanning directory (${DIR}) for Redis configuration files"
             FILES=$(${LSBINARY} ${DIR}/*.conf 2> /dev/null)
-            if [ ! -z "${FILES}" ]; then
+            if [ -n "${FILES}" ]; then
                 ALLFILES="${ALLFILES} ${FILES}"
             else
                 LogText "Result: no configuration files found in this directory"
@@ -279,12 +279,12 @@
                 LogText "Action: checking if ${CONFFILE} is a Sentinel configuration file"
                 # Exclude Sentinel configuration file
                 FIND=$(${GREPBINARY} "^sentinel " ${CONFFILE})
-                if [ ! -z "${FIND}" ]; then
+                if [ -n "${FIND}" ]; then
                     LogText "Result: file is a Sentinel configuration file, skipping it"
                 else
                     LogText "Result: file is NOT a Sentinel configuration file. Now scanning if it is a Redis configuration file"
                     FIND=$(${GREPBINARY} "Redis" ${CONFFILE})
-                    if [ ! -z "${FIND}" ]; then
+                    if [ -n "${FIND}" ]; then
                         REDIS_CONFIGURATION_FILES="${REDIS_CONFIGURATION_FILES} ${CONFFILE}"
                         REDIS_CONFIGURATION_FOUND=1
                         LogText "Result: found a Redis configuration file (${CONFFILE})"
diff --git a/include/tests_dns b/include/tests_dns
index a2732b16..b7cf2ba8 100644
--- a/include/tests_dns
+++ b/include/tests_dns
@@ -38,7 +38,7 @@
 #    # Description : Validate DNSSEC signiture is checked
 #    Register --test-no DNS-1600 --weight L --network YES --category security --description "Validate DNSSEC igniture is checked"
 #    if [ "${SKIPTEST}" -eq 0 ]; then
-#        if [ ! -z "${DIGBINARY}" ]; then
+#        if [ -n "${DIGBINARY}" ]; then
 #
 #            GOOD=$("${DIGBINARY}" +short +time=1 $SIGOKDNS)
 #            BAD=$("${DIGBINARY}" +short +time=1 $SIGFAILDNS)
@@ -47,16 +47,16 @@
 #                LogText "Result: received timeout, can't determine DNSSEC validation"
 #                Display --indent 4 --text "- Checking DNSSEC validation" --result "${STATUS_UNKOWN}" --color YELLOW
 #                #ReportException "${TEST_NO}" "Exception found, both query failed, due to connection timeout"
-#            elif [ -z "${GOOD}" -a ! -z "${BAD}" ]; then
+#            elif [ -z "${GOOD}" -a -n "${BAD}" ]; then
 #                LogText "Result: good signature failed, yet bad signature was accepted"
 #                Display --indent 4 --text "- Checking DNSSEC validation" --result "${STATUS_UNKOWN}" --color YELLOW
 #                #ReportException "${TEST_NO}" "Exception found, OK failed, bad signature was accepted"
-#            elif [ ! -z "${GOOD}" -a ! -z "${BAD}" ]; then
+#            elif [ -n "${GOOD}" -a -n "${BAD}" ]; then
 #                Display --indent 4 --text "- Checking DNSSEC validation" --result "${STATUS_SUGGESTION}" --color YELLOW
 #                LogText "Note: Using DNSSEC validation can protect from DNS hijacking"
 #                #ReportSuggestion "${TEST_NO}" "Altered DNS queries are accepted, configure DNSSEC valdating name servers"
 #                AddHP 2 2
-#            elif [ ! -z "${GOOD}" -a -z "${BAD}" ]; then
+#            elif [ -n "${GOOD}" -a -z "${BAD}" ]; then
 #                Display --indent 4 --text "- Checking DNSSEC validation" --result "${STATUS_OK}" --color GREEN
 #                LogText "Result: altered DNS responses were ignored"
 #                AddHP 0 2
diff --git a/include/tests_file_integrity b/include/tests_file_integrity
index 097cb138..6a527e75 100644
--- a/include/tests_file_integrity
+++ b/include/tests_file_integrity
@@ -70,7 +70,7 @@
 #
     # Test        : FINT-4315
     # Description : Check AIDE configuration file
-    if [ ! -z "${AIDEBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${AIDEBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no FINT-4315 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check AIDE configuration file"
     if [ ${SKIPTEST} -eq 0 ]; then
         AIDE_CONFIG_LOCS="${ROOTDIR}etc ${ROOTDIR}etc/aide ${ROOTDIR}usr/local/etc"
@@ -104,7 +104,7 @@
     Register --test-no FINT-4318 --weight L --network NO --category security --description "Osiris availability"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking Osiris binary"
-        if [ ! -z "${OSIRISBINARY}" ]; then
+        if [ -n "${OSIRISBINARY}" ]; then
             LogText "Result: Osiris is installed (${OSIRISBINARY})"
             Report "file_integrity_tool[]=osiris"
             FILE_INT_TOOL="osiris"
@@ -123,7 +123,7 @@
     Register --test-no FINT-4322 --weight L --network NO --category security --description "Samhain availability"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking Samhain binary"
-        if [ ! -z "${SAMHAINBINARY}" ]; then
+        if [ -n "${SAMHAINBINARY}" ]; then
             LogText "Result: Samhain is installed (${SAMHAINBINARY})"
             Report "file_integrity_tool[]=samhain"
             FILE_INT_TOOL="samhain"
@@ -142,7 +142,7 @@
     Register --test-no FINT-4326 --weight L --network NO --category security --description "Tripwire availability"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking Tripwire binary"
-        if [ ! -z "${TRIPWIREBINARY}" ]; then
+        if [ -n "${TRIPWIREBINARY}" ]; then
             LogText "Result: Tripwire is installed (${TRIPWIREBINARY})"
             Report "file_integrity_tool[]=tripwire"
             FILE_INT_TOOL="tripwire"
@@ -229,7 +229,7 @@
             Display --indent 6 --text "- Configuration status" --result "${STATUS_DISABLED}" --color YELLOW
         fi
         ENABLED=$(${GREPBINARY} "^LF_DIRWATCH =" ${CSF_CONFIG} | ${AWKBINARY} '{ print $3 }' | ${SEDBINARY} 's/\"//g')
-        if [ ! "${ENABLED}" = "0" -a ! -z "${ENABLED}" ]; then
+        if [ ! "${ENABLED}" = "0" -a -n "${ENABLED}" ]; then
             LogText "Result: lfd directory watching is enabled (value: ${ENABLED})"
             Display --indent 6 --text "- Temporary directory watches" --result "${STATUS_ENABLED}" --color GREEN
         else
@@ -237,7 +237,7 @@
             Display --indent 6 --text "- Temporary directory watches" --result "${STATUS_DISABLED}" --color YELLOW
         fi
         ENABLED=$(${GREPBINARY} "^LF_DIRWATCH_FILE =" ${CSF_CONFIG} | ${AWKBINARY} '{ print $3 }' | ${SEDBINARY} 's/\"//g')
-        if [ ! "${ENABLED}" = "0" -a ! -z "${ENABLED}" ]; then
+        if [ ! "${ENABLED}" = "0" -a -n "${ENABLED}" ]; then
             Display --indent 6 --text "- Directory/File watches" --result "${STATUS_ENABLED}" --color GREEN
         else
             Display --indent 6 --text "- Directory/File watches" --result "${STATUS_DISABLED}" --color YELLOW
@@ -267,7 +267,7 @@
 #
     # Test        : FINT-4402 (was FINT-4316)
     # Description : Check if AIDE is configured to use SHA256 or SHA512 checksums
-    if [ ! "${AIDEBINARY}" = "" -a ! -z "${AIDECONFIG}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ! "${AIDEBINARY}" = "" -a -n "${AIDECONFIG}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no FINT-4402 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "AIDE configuration: Checksums (SHA256 or SHA512)"
     if [ ${SKIPTEST} -eq 0 ]; then
         FIND=$(${GREPBINARY} -v "^#" ${AIDECONFIG} | ${EGREPBINARY} "= .*(sha256|sha512)")
diff --git a/include/tests_filesystems b/include/tests_filesystems
index 4e52ea5e..ac0c1d3c 100644
--- a/include/tests_filesystems
+++ b/include/tests_filesystems
@@ -89,7 +89,7 @@
                  ReportException "${TEST_NO}:1" "Don't know this specific operating system yet, while volume group manager was found"
             ;;
         esac
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             LogText "Result: found one or more volume groups"
             for I in ${FIND}; do
                 LogText "Found LVM volume group: ${I}"
@@ -152,7 +152,7 @@
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking for Linux EXT file systems"
         FIND=$(${MOUNTBINARY} -t ext2,ext3,ext4 | ${AWKBINARY} '{ print $3","$5 }')
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             LogText "Result: found one or more EXT file systems"
             for I in ${FIND}; do
                 FILESYSTEM=$(echo ${I} | ${CUTBINARY} -d ',' -f1)
@@ -173,7 +173,7 @@
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking for Linux XFS file systems"
         FIND=$(${MOUNTBINARY} -t xfs | ${AWKBINARY} '{ print $3","$5 }')
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             LogText "Result: found one or more XFS file systems"
             for I in ${FIND}; do
                 FILESYSTEM=$(echo ${I} | ${CUTBINARY} -d ',' -f1)
@@ -272,12 +272,12 @@
 
             # Test for UUID usage (e.g. UUID=uuid --> /dev/disk/by-uuid/<uuid>)
             HAS_UUID=$(echo ${I} | ${GREPBINARY} "^UUID=")
-            if [ ! -z "${HAS_UUID}" ]; then
+            if [ -n "${HAS_UUID}" ]; then
                 UUID=$(echo ${HAS_UUID} | ${AWKBINARY} -F= '{ print $2 }')
                 LogText "Result: Using ${UUID} as UUID"
-                if [ ! -z "${BLKIDBINARY}" ]; then
+                if [ -n "${BLKIDBINARY}" ]; then
                     FIND2=$(${BLKIDBINARY} | ${AWKBINARY} '{ if ($2=="UUID=\"${UUID}\"") print $1 }' | ${SEDBINARY} 's/:$//')
-                    if [ ! -z "${FIND2}" ]; then
+                    if [ -n "${FIND2}" ]; then
                         REAL="${FIND2}"
                     fi
                 else
@@ -286,7 +286,7 @@
                     if [ -L /dev/disk/by-uuid/${UUID} ]; then
                         LogText "Result: found disk via /dev/disk/by-uuid listing"
                         ShowSymlinkPath /dev/disk/by-uuid/${UUID}
-                        if [ ! -z "${sFILE}" ]; then
+                        if [ -n "${sFILE}" ]; then
                             REAL="${sFILE}"
                             LogText "Result: disk is ${REAL}"
                         fi
@@ -342,7 +342,7 @@
     if [ "${OS}" = "Linux" -a -f ${ROOTDIR}proc/version ]; then
         LINUX_KERNEL_MAJOR=$(echo $OS_KERNELVERSION | ${AWKBINARY} -F. '{print $1}')
         LINUX_KERNEL_MINOR=$(echo $OS_KERNELVERSION | ${AWKBINARY} -F. '{print $2}')
-        if [ ! -z "${LINUX_KERNEL_MAJOR}" -a ! -z "${LINUX_KERNEL_MINOR}" ]; then
+        if [ -n "${LINUX_KERNEL_MAJOR}" -a -n "${LINUX_KERNEL_MINOR}" ]; then
             if [ ${LINUX_KERNEL_MAJOR} -ge 3 -a ${LINUX_KERNEL_MINOR} -ge 3 ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
         else
             PREQS_MET="NO";
@@ -464,7 +464,7 @@
         FOUND=0
         LogText "Test: Checking acl option on ext[2-4] root file system"
         FIND=$(${MOUNTBINARY} | ${AWKBINARY} '{ if ($3=="/" && $5~/ext[2-4]/) { print $6 } }' | ${GREPBINARY} acl)
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             LogText "Result: found ACL option"
             FOUND=1
         else
@@ -480,11 +480,11 @@
                 FIND1=$(${MOUNTBINARY} -t ext2,ext3,ext4 | ${GREPBINARY} "on / " | ${AWKBINARY} '{ print $1 }')
             fi
             # Trying to determine default mount options from EXT2/EXT3/EXT4 file systems
-            if [ ! -z "${FIND1}" ]; then
+            if [ -n "${FIND1}" ]; then
                 LogText "Result: found ${FIND1}"
                 LogText "Test: Checking default options on ${FIND1}"
                 FIND2=$(${TUNE2FSBINARY} -l ${FIND1} 2> /dev/null | ${GREPBINARY} "^Default mount options" | ${GREPBINARY} "acl")
-                if [ ! -z "${FIND2}" ]; then
+                if [ -n "${FIND2}" ]; then
                     LogText "Result: found ACL option in default mount options"
                     FOUND=1
                 else
@@ -528,7 +528,7 @@
             NOEXEC=$(echo ${FIND} | ${AWKBINARY} '{ if ($1 ~ "noexec") { print "YES" } else { print "NO" } }')
             NOSUID=$(echo ${FIND} | ${AWKBINARY} '{ if ($1 ~ "nosuid") { print "YES" } else { print "NO" } }')
 
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 LogText "Result: mount system / is configured with options: ${FIND}"
                 if [ "${FIND}" = "defaults" ]; then
                     Display --indent 2 --text "- Mount options of /" --result "${STATUS_OK}" --color GREEN
@@ -577,7 +577,7 @@
                         FS_FSTAB=""
                     fi
                 fi
-                if [ ! -z "${FS_FSTAB}" ]; then
+                if [ -n "${FS_FSTAB}" ]; then
                     FOUND_FLAGS=$(${AWKBINARY} -v fs=${FILESYSTEM} '{ if ($2==fs) { print $4 } }' ${ROOTDIR}etc/fstab | ${SEDBINARY} 's/,/ /g' | ${TRBINARY} '\n' ' ')
                     LogText "File system:    ${FILESYSTEM}"
                     LogText "Expected flags: ${EXPECTED_FLAGS}"
@@ -629,7 +629,7 @@
         if [ -f ${ROOTDIR}etc/fstab ]; then
             FIND=$(${AWKBINARY} '{ if ($2=="/var/tmp") { print $4 } }' ${ROOTDIR}etc/fstab)
             BIND=$(echo ${FIND} | ${AWKBINARY} '{ if ($1 ~ "bind") { print "YES" } else { print "NO" } }')
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 LogText "Result: mount system /var/tmp is configured with options: ${FIND}"
                 if [ "${BIND}" = "YES" ]; then
                     Display --indent 2 --text "- /var/tmp is bound to /tmp" --result "${STATUS_OK}" --color GREEN
@@ -760,7 +760,7 @@
     # Data        : cramfs freevxfs hfs hfsplus jffs2 squashfs udf 
     Register --test-no FILE-6430 --weight L --network NO --category security --description "Disable mounting of some filesystems"
     if [ ${SKIPTEST} -eq 0 ]; then
-        if [ ! -z "${LSMODBINARY}" -a -f /proc/modules ]; then
+        if [ -n "${LSMODBINARY}" -a -f /proc/modules ]; then
             Display --indent 2 --text "- Disable kernel support of some filesystems"
             LIST_FS_NOT_SUPPORTED="cramfs freevxfs hfs hfsplus jffs2 squashfs udf"
             FOUND=0
@@ -769,7 +769,7 @@
             for FS in ${LIST_FS_NOT_SUPPORTED}; do
                 # Check if filesystem is present in modprobe output
                 FIND=$(${MODPROBEBINARY} -v -n $FS 2>/dev/null | ${EGREPBINARY} "/${FS}.ko" | tail -1)
-                if [ ! -z "${FIND}" ]; then
+                if [ -n "${FIND}" ]; then
                     LogText "Result: found module support in kernel: ${FIND}"
                     Debug "Module ${FS} present in the kernel"
                     LogText "Test: Checking if ${FS} is active"
diff --git a/include/tests_firewalls b/include/tests_firewalls
index 735059fe..99a9bc2a 100644
--- a/include/tests_firewalls
+++ b/include/tests_firewalls
@@ -41,7 +41,7 @@
     Register --test-no FIRE-4502 --os Linux --weight L --network NO --category security --description "Check iptables kernel module"
     if [ ${SKIPTEST} -eq 0 ]; then
         FIND=$(${LSMODBINARY} | ${AWKBINARY} '{ print $1 }' | ${GREPBINARY} "^ip*_tables")
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             FIREWALL_ACTIVE=1
             IPTABLES_ACTIVE=1
             IPTABLES_MODULE_ACTIVE=1
@@ -73,11 +73,11 @@
             # If we have a kernel configuration file, use it for testing
             # Do not perform test if we already found it in kernel module list, to avoid triggered it in the upcoming
             # tests, when using iptables --list
-            if [ ! -z "${LINUXCONFIGFILE}" ]; then
+            if [ -n "${LINUXCONFIGFILE}" ]; then
                 if [ -f ${LINUXCONFIGFILE} -a ${IPTABLES_MODULE_ACTIVE} -eq 0 ]; then
                     LogText "Result: found kernel configuration file (${LINUXCONFIGFILE})"
                     FIND=$(${tCATCMD} ${LINUXCONFIGFILE} | ${GREPBINARY} -v '^#' | ${GREPBINARY} "CONFIG_IP_NF_IPTABLES" | head -n 1)
-                    if [ ! -z "${FIND}" ]; then
+                    if [ -n "${FIND}" ]; then
                         HAVEMOD=$(echo ${FIND} | ${CUTBINARY} -d '=' -f2)
                         # Do not use iptables if it's compiled as a module (=m), since we already tested for it in the
                         # active list.
@@ -151,11 +151,11 @@
 #
     # Test        : FIRE-4512
     # Description : Check iptables for empty ruleset (should have at least 5 or more rules)
-    if [ ! -z "${IPTABLESBINARY}" -a ${IPTABLES_ACTIVE} -eq 1 ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${IPTABLESBINARY}" -a ${IPTABLES_ACTIVE} -eq 1 ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no FIRE-4512 --preqs-met ${PREQS_MET} --os Linux --weight L --network NO --root-only YES --category security --description "Check iptables for empty ruleset"
     if [ ${SKIPTEST} -eq 0 ]; then
         FIND=$(${IPTABLESBINARY} --list --numeric 2> /dev/null | ${EGREPBINARY} -v "^(Chain|target|$)" | ${WCBINARY} -l | ${TRBINARY} -d ' ')
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             FIREWALL_ACTIVE=1
             if [ ${FIND} -le 5 ]; then
                 # Firewall is active, but needs configuration
@@ -174,7 +174,7 @@
 #
     # Test        : FIRE-4513
     # Description : Check iptables for unused rules
-    if [ ! -z "${IPTABLESBINARY}" -a ${IPTABLES_ACTIVE} -eq 1 ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${IPTABLESBINARY}" -a ${IPTABLES_ACTIVE} -eq 1 ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no FIRE-4513 --preqs-met ${PREQS_MET} --os Linux --weight L --network NO --root-only YES --category security --description "Check iptables for unused rules"
     if [ ${SKIPTEST} -eq 0 ]; then
         FIND=$(${IPTABLESBINARY} --list --numeric --line-numbers --verbose | ${AWKBINARY} '{ if ($2=="0") print $1 }' | ${XARGSBINARY})
@@ -212,7 +212,7 @@
 
         # Check status with pfctl
         LogText "Test: checking pf status via pfctl"
-        if [ ! -z "${PFCTLBINARY}" ]; then
+        if [ -n "${PFCTLBINARY}" ]; then
             FIND=$(${PFCTLBINARY} -sa 2>&1 | ${GREPBINARY} "^Status" | ${HEADBINARY} -1 | ${AWKBINARY} '{ print $2 }')
             if [ "${FIND}" = "Disabled" ]; then
                 if IsVerbose; then Display --indent 2 --text "- Checking pf status (pfctl)" --result "${STATUS_DISABLED}" --color RED; fi
@@ -233,7 +233,7 @@
         if [ ${PFFOUND} -eq 0 ]; then
             # Check for pf kernel module (FreeBSD and similar)
             LogText "Test: searching for pf kernel module"
-            if [ ! -z "${KLDSTATBINARY}" ]; then
+            if [ -n "${KLDSTATBINARY}" ]; then
                 FIND=$(${KLDSTATBINARY} | ${GREPBINARY} 'pf.ko')
                 if [ -z "${FIND}" ]; then
                     LogText "Result: Can not find pf KLD"
@@ -353,7 +353,7 @@
     # Description : Check IPFW (FreeBSD)
     Register --test-no FIRE-4530 --os FreeBSD --weight L --network NO --category security --description "Check IPFW status"
     if [ ${SKIPTEST} -eq 0 ]; then
-        if [ ! -z "${SYSCTLBINARY}" ]; then
+        if [ -n "${SYSCTLBINARY}" ]; then
             # For now, only check for IPv4.
             FIND=$(${SYSCTLBINARY} net.inet.ip.fw.enable 2> /dev/null | ${AWKBINARY} '{ print $2 }')
             if [ "${FIND}" = "1" ]; then
@@ -386,7 +386,7 @@
     Register --test-no FIRE-4532 --weight L --os "macOS" --preqs-met ${PREQS_MET} --network NO --category security --description "Check macOS application firewall"
     if [ ${SKIPTEST} -eq 0 ]; then
         FIND=$(/usr/libexec/ApplicationFirewall/socketfilterfw --getglobalstate 2> /dev/null | ${GREPBINARY} "Firewall is enabled")
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             Display --indent 2 --text "- Checking macOS: Application Firewall" --result "${STATUS_ENABLED}" --color GREEN
             AddHP 3 3
             LogText "Result: application firewall of macOS is enabled"
@@ -478,7 +478,7 @@
     Register --test-no FIRE-4536 --os Linux --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check nftables status"
     if [ ${SKIPTEST} -eq 0 ]; then
         FIND=$(${LSMODBINARY} | ${AWKBINARY} '{ print $1 }' | ${GREPBINARY} "^nf*_tables")
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             LogText "Result: found nftables kernel module"
             FIREWALL_ACTIVE=1
             NFTABLES_ACTIVE=1
@@ -526,7 +526,7 @@
     Register --test-no FIRE-4586 --preqs-met ${PREQS_MET} --weight L --network NO --root-only YES --category security --description "Check firewall logging"
     if [ ${SKIPTEST} -eq 0 ]; then
         if [ ${IPTABLES_ACTIVE} -eq 1 ]; then
-            if [ ! -z "${IPTABLESSAVEBINARY}" ]; then
+            if [ -n "${IPTABLESSAVEBINARY}" ]; then
                 HAS_LOGGING=$(${IPTABLESSAVEBINARY} | ${GREPBINARY} "\-j LOG")
                 if [ -z "${HAS_LOGGING}" ]; then
                     Report "firewall_no_logging[]=iptables"
@@ -563,7 +563,7 @@
     # Test        : FIRE-4594
     # Description : Check for APF (Advanced Policy Firewall)
     Register --test-no FIRE-4594 --weight L --network NO --category security --description "Check for APF presence"
-    if [ ! -z "${IPTABLESBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${IPTABLESBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     if [ ${SKIPTEST} -eq 0 ]; then
         FILE="/etc/apf/conf.apf"
         LogText "Test: check ${FILE}"
diff --git a/include/tests_hardening b/include/tests_hardening
index 0719cf8e..006df683 100644
--- a/include/tests_hardening
+++ b/include/tests_hardening
@@ -59,7 +59,7 @@
                 FILE="${ITEM}"
                 LogText "Test: Check file permissions for ${ITEM}"
                 ShowSymlinkPath ${ITEM}
-                if [ ! -z "${SYMLINK}" ]; then
+                if [ -n "${SYMLINK}" ]; then
                     FILE="${SYMLINK}"
                 fi
 
diff --git a/include/tests_homedirs b/include/tests_homedirs
index 9570816b..e51cf3d9 100644
--- a/include/tests_homedirs
+++ b/include/tests_homedirs
@@ -114,7 +114,7 @@
     # Description : Check for suspicious shell history files
     Register --test-no HOME-9310 --weight L --network NO --category security --description "Checking for suspicious shell history files"
     if [ ${SKIPTEST} -eq 0 ]; then
-        if [ ! -z "${HOMEDIRS}" ]; then
+        if [ -n "${HOMEDIRS}" ]; then
             if [ "${OS}" = "Solaris" ]; then
                 # Solaris doesn't support -maxdepth
                 FIND=$(${FINDBINARY} ${HOMEDIRS} -name ".*history" ! -type f -print)
@@ -152,7 +152,7 @@
     # Notes       : For performance reasons we combine the scanning of different files, so inode caching is used
     #               as much as possible for every find command
     # Profile opt : ignore-home-dir (multiple lines allowed), ignores home directory
-    if [ ! -z "${REPORTFILE}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${REPORTFILE}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no HOME-9350 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Collecting information from home directories"
     if [ ${SKIPTEST} -eq 0 ]; then
         IGNORE_HOME_DIRS=$(${GREPBINARY} "^ignore-home-dir=" ${REPORTFILE} | ${AWKBINARY} -F= '{ print $2 }')
diff --git a/include/tests_insecure_services b/include/tests_insecure_services
index df616e56..3ba08570 100644
--- a/include/tests_insecure_services
+++ b/include/tests_insecure_services
@@ -222,7 +222,7 @@
                 if [ -f "${FILE}" ]; then
                     LogText "Test: checking status in xinetd configuration file (${FILE})"
                     FIND=$(${GREPBINARY} "disable\s*=\s*no" ${FILE})
-                    if [ ! -z "${FIND}" ]; then
+                    if [ -n "${FIND}" ]; then
                         LogText "Result: found insecure service enabled: ${SERVICE}"
                         XINETD_INSECURE_SERVICE_FOUND=1
                         ReportSuggestion "${TEST_NO}" "Disable or remove any insecure services in the xinetd configuration" "${SERVICE}" "text:See log file for more details"
@@ -492,7 +492,7 @@
 #
 #################################################################################
 #
-    if [ ! -z "${LAUNCHCTL_BINARY}" ]; then PREQS_MET="YES"; SKIPREASON=""; else PREQS_MET="NO"; SKIPREASON="No launchctl binary on this system"; fi
+    if [ -n "${LAUNCHCTL_BINARY}" ]; then PREQS_MET="YES"; SKIPREASON=""; else PREQS_MET="NO"; SKIPREASON="No launchctl binary on this system"; fi
     Register --test-no INSE-8050 --os "macOS" --preqs-met ${PREQS_MET} --skip-reason "${SKIPREASON}" --weight M --network NO --category security --description "Check for insecure services on macOS"
     if [ ${SKIPTEST} -eq 0 ]; then
         TEST_SERVICES="com.apple.fingerd"
diff --git a/include/tests_kernel b/include/tests_kernel
index 7a542c3d..2ffd8df9 100644
--- a/include/tests_kernel
+++ b/include/tests_kernel
@@ -183,7 +183,7 @@
     # Description : Check if Linux is build as a monolithic kernel or not
     Register --test-no KRNL-5723 --os Linux --weight L --network NO --category security --description "Determining if Linux kernel is monolithic"
     if [ ${SKIPTEST} -eq 0 ]; then
-        if [ ! -z "${LSMODBINARY}" -a -f /proc/modules ]; then
+        if [ -n "${LSMODBINARY}" -a -f /proc/modules ]; then
             LogText "Test: checking if kernel is monolithic or modular"
             # Checking if any modules are loaded
             FIND=$(${LSMODBINARY} | ${GREPBINARY} -v "^Module" | wc -l | ${TRBINARY} -s ' ' | ${TRBINARY} -d ' ')
@@ -208,7 +208,7 @@
     # Description : Checking Linux loaded kernel modules
     Register --test-no KRNL-5726 --os Linux --weight L --network NO --category security --description "Checking Linux loaded kernel modules"
     if [ ${SKIPTEST} -eq 0 ]; then
-        if [ ! -z "${LSMODBINARY}" -a -f /proc/modules ]; then
+        if [ -n "${LSMODBINARY}" -a -f /proc/modules ]; then
             FIND=$(${LSMODBINARY} | ${AWKBINARY} '{ if ($1!="Module") print $1 }' | sort)
             Display --indent 2 --text "- Checking loaded kernel modules" --result "${STATUS_DONE}" --color GREEN
             if HasData "${FIND}"; then
@@ -519,7 +519,7 @@
         if [ -d ${ROOTDIR}boot ]; then
             LogText "Result: /boot exists, performing more tests from here"
             FIND=$(${LSBINARY} ${ROOTDIR}boot/* 2> /dev/null)
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 if [ -f ${ROOTDIR}boot/vmlinuz -a ! -L ${ROOTDIR}boot/vmlinuz ]; then
                     LogText "Result: found /boot/vmlinuz (not symlinked)"
                     NEXTLINE=0
@@ -532,7 +532,7 @@
                             if [ "${I}" = "version" ]; then NEXTLINE=1; fi
                         fi
                     done
-                    if [ ! -z "${FINDVERSION}" ]; then
+                    if [ -n "${FINDVERSION}" ]; then
                         CURRENT_KERNEL=$(uname -r)
                         if [ ! "${CURRENT_KERNEL}" = "${FINDVERSION}" ]; then
                             LogText "Result: reboot needed, as current kernel is different than the one loaded"
@@ -545,7 +545,7 @@
                     LogText "Result: /found /boot/vmlinuz-linux (usually Arch Linux or similar)"
                     LogText "Test: checking kernel version on disk"
                     VERSION_ON_DISK=$(${FILEBINARY} -b ${ROOTDIR}boot/vmlinuz-linux | ${AWKBINARY} '{ if ($1=="Linux" && $7=="version") { print $8 }}')
-                    if [ ! -z "${VERSION_ON_DISK}" ]; then
+                    if [ -n "${VERSION_ON_DISK}" ]; then
                         LogText "Result: found version ${VERSION_ON_DISK}"
                         ACTIVE_KERNEL=$(uname -r)
                         LogText "Result: active kernel version ${ACTIVE_KERNEL}"
@@ -570,7 +570,7 @@
                     MYKERNEL=$(${UNAMEBINARY} -r | ${SEDBINARY} 's/\.[a-z].*.//g' | ${SEDBINARY} 's/-[a-z].*.//g' | ${SEDBINARY} 's/-/./g')
                     LogText "Result: using ${MYKERNEL} as my kernel version (stripped)"
                     FIND=$(ls ${ROOTDIR}boot/vmlinuz* 2> /dev/null)
-                    if [ ! -z "${FIND}" ]; then
+                    if [ -n "${FIND}" ]; then
                         for ITEM in ${FIND}; do
                             LogText "Result: found ${ITEM}"
                         done
@@ -586,11 +586,11 @@
                         # Examples:
                         # /boot/kernel-genkernel-x86_64-3.14.14-gentoo
                         KERNELS=$(${LSBINARY} ${ROOTDIR}boot/kernel* | ${AWKBINARY} -F- '{ if ($2=="genkernel") { print $4 }}' | ${GREPBINARY} "^[0-9]" | ${SORTBINARY} -n -k1,1 -k2,2 -k3,3 -k4,4 -k5,5 -k6,6 -t \.)
-                        if [ ! -z "${KERNELS}" ]; then LogText "Output: ${KERNELS}"; fi
+                        if [ -n "${KERNELS}" ]; then LogText "Output: ${KERNELS}"; fi
                     else
                         ReportException "${TEST_NO}:2" "Can not find any vmlinuz or kernel files in /boot, which is unexpected"
                     fi
-                    if [ ! -z "${KERNELS}" ]; then
+                    if [ -n "${KERNELS}" ]; then
                         FOUND_KERNEL=0
                         for I in ${KERNELS}; do
                             # Check if we already found a kernel and it is not equal to what we run (e.g. double versions may exist)
diff --git a/include/tests_kernel_hardening b/include/tests_kernel_hardening
index 71ed901e..eba7504d 100644
--- a/include/tests_kernel_hardening
+++ b/include/tests_kernel_hardening
@@ -47,7 +47,7 @@
         done
 
         # Scan custom profile
-        if [ ! -z "${CUSTOM_PROFILE}" ]; then
+        if [ -n "${CUSTOM_PROFILE}" ]; then
             FIND=$(${GREPBINARY} "^config-data=sysctl;" ${CUSTOM_PROFILE} | ${SEDBINARY} 's/ /-space-/g')
             for LINE in ${FIND}; do
                 SYSCTLKEY=$(echo ${LINE} | ${AWKBINARY} -F\; '{ print $2 }')
@@ -57,7 +57,7 @@
         fi
 
         # Last, use data from default profile
-        if [ ! -z "${DEFAULT_PROFILE}" ]; then
+        if [ -n "${DEFAULT_PROFILE}" ]; then
             FIND=$(${GREPBINARY} "^config-data=sysctl;" ${DEFAULT_PROFILE} | ${SEDBINARY} 's/ /-space-/g')
             for LINE in ${FIND}; do
                 SYSCTLKEY=$(echo ${LINE} | ${AWKBINARY} -F\; '{ print $2 }')
@@ -76,7 +76,7 @@
                 tFINDhp=$(echo ${line} | ${AWKBINARY} -F\; '{ print $4 }' | ${GREPBINARY} "[0-9]")
                 tFINDdesc=$(echo ${line} | ${AWKBINARY} -F\; '{ print $5 }' | ${SEDBINARY} 's/-space-/ /g')
                 tFINDcurvalue=$(${SYSCTL_READKEY} ${tFINDkey} 2> /dev/null)
-                if [ ! -z "${tFINDcurvalue}" ]; then
+                if [ -n "${tFINDcurvalue}" ]; then
                     positive_match=0
                     for value in ${tFINDexpvalue}; do
                         if [ "${value}" = "${tFINDcurvalue}" ]; then
diff --git a/include/tests_ldap b/include/tests_ldap
index ae4a9599..0c6ae10e 100644
--- a/include/tests_ldap
+++ b/include/tests_ldap
@@ -66,7 +66,7 @@
             fi
         done
         # Check if we found a valid location
-        if [ ! -z "${SLAPD_CONF_LOCATION}" ]; then
+        if [ -n "${SLAPD_CONF_LOCATION}" ]; then
             Display --indent 4 --text "- Checking slapd.conf" --result "${STATUS_FOUND}" --color GREEN
         else
             Display --indent 4 --text "- Checking slapd.conf" --result "${STATUS_NOT_FOUND}" --color YELLOW
diff --git a/include/tests_logging b/include/tests_logging
index c7995b47..f8492c90 100644
--- a/include/tests_logging
+++ b/include/tests_logging
@@ -262,7 +262,7 @@
 #
     # Test        : LOGG-2148
     # Description : Checking log files rotated with logrotate
-    if [ ! -z "${LOGROTATEBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${LOGROTATEBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no LOGG-2148 --weight L --preqs-met ${PREQS_MET} --network NO --category security --description "Checking logrotated files"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking which files are rotated with logrotate and if they exist"
@@ -311,7 +311,7 @@
         # Try local hosts file
         LogText "Result: Checking for loghost in /etc/inet/hosts"
         FIND=$(${GREPBINARY} loghost /etc/inet/hosts | ${GREPBINARY} -v "^#")
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             SOLARIS_LOGHOST_FOUND=1
             LogText "Result: Found loghost entry in /etc/inet/hosts"
         else
@@ -320,7 +320,7 @@
             # Try name resolving if no entry is present in local host file
             LogText "Result: Checking for loghost via name resolving"
             FIND=$(getent hosts loghost | ${GREPBINARY} loghost)
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 SOLARIS_LOGHOST_FOUND=1
                 LogText "Result: name resolving was successful"
                 LogText "Output: ${FIND}"
@@ -356,7 +356,7 @@
         if [ -f ${SYSLOGD_CONF} ]; then
             LogText "Test: check if logs are also logged to a remote logging host"
             FIND=$(${EGREPBINARY} "@[a-zA-Z0-9]|destination\s.+(udp|tcp).+\sport" ${SYSLOGD_CONF} | ${GREPBINARY} -v "^#" | ${GREPBINARY} -v "[a-zA-Z0-9]@")
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 LogText "Result: remote logging enabled"
                 REMOTE_LOGGING_ENABLED=1
             else
@@ -364,7 +364,7 @@
                 DESTINATIONS=$(${GREPBINARY} "^destination" ${SYSLOGD_CONF} | ${EGREPBINARY} "(udp|tcp)" | ${GREPBINARY} "port" | ${AWKBINARY} '{print $2}')
                 for DESTINATION in ${DESTINATIONS}; do
                     FIND2=$(${GREPBINARY} "log" ${SYSLOGD_CONF} | ${GREPBINARY} "source" | ${EGREPBINARY} "destination\(${DESTINATION}\)")
-                    if [ ! -z "${FIND2}" = "" ]; then
+                    if [ -n "${FIND2}" = "" ]; then
                         LogText "Result: found destination ${DESTINATION} configured for remote logging"
                         REMOTE_LOGGING_ENABLED=1
                     fi
@@ -461,7 +461,7 @@
     Register --test-no LOGG-2180 --weight L --network NO --category security --description "Checking open log files"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: checking open log files with lsof"
-        if [ ! -z "${LSOFBINARY}" ]; then
+        if [ -n "${LSOFBINARY}" ]; then
             FIND=$(${LSOFBINARY} -n 2>&1 | ${GREPBINARY} "log$" | ${EGREPBINARY} -v "WARNING|Output information" | ${AWKBINARY} '{ if ($5=="REG") { print $9 } }' | ${SORTBINARY} -u | ${GREPBINARY} -v "^$")
             for I in ${FIND}; do
                 LogText "Found logfile: ${I}"
@@ -477,7 +477,7 @@
 #
     # Test        : LOGG-2190
     # Description : Checking deleted files
-    if [ ! -z "${LSOFBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${LSOFBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no LOGG-2190 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Checking for deleted files in use"
     if [ ${SKIPTEST} -eq 0 ]; then
         EARLY_MYSQL=""
@@ -486,12 +486,12 @@
         LSOF_GREP="WARNING|Output information"
 
         # MySQL versions prior to 5.6 leave lots of deleted in-use files in /tmp, ignoring those
-        if [ ! -z "${DPKGBINARY}" ]; then
+        if [ -n "${DPKGBINARY}" ]; then
             EARLY_MYSQL=$(${DPKGBINARY} -l | ${EGREPBINARY} mysql-server-5.[0-5])
-        elif [ ! -z "${RPMBINARY}" ]; then
+        elif [ -n "${RPMBINARY}" ]; then
             EARLY_MYSQL=$(${RPMBINARY} -qa mariadb | ${EGREPBINARY} mariadb-5.[0-5])
         fi
-        if [ ! -z "${EARLY_MYSQL}" ]; then LSOF_GREP="${LSOF_GREP}|mysqld"; fi
+        if [ -n "${EARLY_MYSQL}" ]; then LSOF_GREP="${LSOF_GREP}|mysqld"; fi
 
         # grsecurity causes Fail2Ban to hold onto deleted in-use files in /var/tmp
         if [ ${GRSEC_FOUND} -eq 1 ]; then LSOF_GREP="${LSOF_GREP}|fail2ban"; fi
@@ -501,7 +501,7 @@
         fi
 
         FIND=$(${LSOFBINARY} -n +L 1 2>&1 | ${EGREPBINARY} -vw "${LSOF_GREP}" | ${EGREPBINARY} -v '/dev/zero|/\[aio\]' | ${AWKBINARY} '{ if ($5=="REG") { printf "%s(%s)\n", $10, $1 } }' | ${GREPBINARY} -v "^$" | ${SORTBINARY} -u)
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             LogText "Result: found one or more files which are deleted, but still in use"
             for I in ${FIND}; do
                 LogText "Found deleted file: ${I}"
@@ -523,7 +523,7 @@
     Register --test-no LOGG-2192 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Checking for open log files that are empty"
     if [ ${SKIPTEST} -eq 0 ]; then
         FIND=$(${LSOFBINARY} -n -w | ${AWKBINARY} '{if ($5=="REG" && $7=="0" && $9 ~ /log$/) {print $1","$9}}' | ${SORTBINARY} | uniq)
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             for I in ${FIND}; do
                 LogText "Found an opened logfile that is empty: ${I}"
                 Report "open_empty_log_file[]=${I}"
diff --git a/include/tests_mac_frameworks b/include/tests_mac_frameworks
index 516a501e..14b34e4a 100644
--- a/include/tests_mac_frameworks
+++ b/include/tests_mac_frameworks
@@ -50,7 +50,7 @@
     if [ ${APPARMORFOUND} -eq 1 ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no MACF-6208 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check if AppArmor is enabled"
     if [ ${SKIPTEST} -eq 0 ]; then
-        if [ ! -z "${AASTATUSBINARY}" ]; then
+        if [ -n "${AASTATUSBINARY}" ]; then
             CAN_READ_FILE=0
             FILE="/sys/kernel/security/apparmor/profiles"
             if [ -f ${FILE} ]; then
@@ -114,7 +114,7 @@
     Register --test-no MACF-6232 --weight L --network NO --category security --description "Check SELINUX presence"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: checking if we have sestatus binary"
-        if [ ! -z "${SESTATUSBINARY}" ]; then
+        if [ -n "${SESTATUSBINARY}" ]; then
             LogText "Result: found sestatus binary (${SESTATUSBINARY})"
             Display --indent 2 --text "- Checking presence SELinux" --result "${STATUS_FOUND}" --color GREEN
         else
@@ -206,7 +206,7 @@
     Register --test-no RBAC-6272 --weight L --network NO --category security --description "Check grsecurity presence"
     if [ ${SKIPTEST} -eq 0 ]; then
         # Check Linux kernel configuration
-        if [ ! -z "${LINUXCONFIGFILE}" -a -f "${LINUXCONFIGFILE}" ]; then
+        if [ -n "${LINUXCONFIGFILE}" -a -f "${LINUXCONFIGFILE}" ]; then
             FIND=$(${GREPBINARY} ^CONFIG_GRKERNSEC=y ${LINUXCONFIGFILE})
             if [ ! "${FIND}" = "" ]; then
                 LogText "Result: grsecurity available (in kernel config)"
diff --git a/include/tests_mail_messaging b/include/tests_mail_messaging
index b74a7c5e..f5770bc2 100644
--- a/include/tests_mail_messaging
+++ b/include/tests_mail_messaging
@@ -77,20 +77,20 @@
         # Smarthost or Satellite
         FIND3=$(echo "${EXIM_ROUTERS}" | ${EGREPBINARY} '^smarthost')
 
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             EXIM_TYPE="LOCAL ONLY"
-        elif [ ! -z "${FIND2}" ]; then
+        elif [ -n "${FIND2}" ]; then
             EXIM_TYPE="INTERNET HOST"
-        elif [ ! -z "${FIND3}" ]; then
+        elif [ -n "${FIND3}" ]; then
             FIND4=$(echo "${EXIM_ROUTERS}" | ${EGREPBINARY} '^hub_user_smarthost')
-            if [ ! -z "${FIND4}" ]; then
+            if [ -n "${FIND4}" ]; then
                 EXIM_TYPE="SATELLITE"
             else
                 EXIM_TYPE="SMARTHOST"
             fi
         fi
 
-        if [ ! -z "${EXIM_TYPE}" ]; then
+        if [ -n "${EXIM_TYPE}" ]; then
             LogText "Result: Exim Type - ${EXIM_TYPE}"
             Display --indent 4 --text "- Type" --result "${EXIM_TYPE}" --color GREEN
         else
@@ -101,7 +101,7 @@
         if [ "${EXIM_TYPE}" = "INTERNET HOST" -o "${EXIM_TYPE}" = "SMARTHOST" ]; then
             LogText "Test: Exim Public Interfaces"
             EXIM_IP=$(exim -bP local_interfaces | cut -d '=' -f2 | sed -e 's/\s*<\s*\;\?//' -e 's/\s*::0\s*\;\?//' -e 's/\s*127.0.0.1\s*\;\?//' -e 's/^\s*//' -e 's/\s*$//')
-            if [ ! -z "${EXIM_IP}" ]; then
+            if [ -n "${EXIM_IP}" ]; then
                 LogText "Result: ${EXIM_IP}"
                 Display --indent 4 --text "- Public Interface(s)" --result "${EXIM_IP}" --color GREEN
             else
@@ -111,7 +111,7 @@
 
             LogText "Test: Exim TLS State"
             EXIM_TLS=$(exim -bP tls_advertise_hosts | cut -d '=' -f2 | sed -e 's/^\s*//' -e 's/\s*$//')
-            if [ ! -z "${EXIM_TLS}" ]; then
+            if [ -n "${EXIM_TLS}" ]; then
                 LogText "Result: Enabled"
                 Display --indent 4 --text "- TLS" --result "ENABLED" --color GREEN
             else
@@ -120,7 +120,7 @@
             fi
         fi
 
-        if [ ! -z "${EXIM_TYPE}" -a "${EXIM_TYPE}" != "LOCAL ONLY" ]; then
+        if [ -n "${EXIM_TYPE}" -a "${EXIM_TYPE}" != "LOCAL ONLY" ]; then
             LogText "Test: Exim Certificate and Private Key"
 
             case "${EXIM_TYPE}" in
@@ -134,7 +134,7 @@
                     ;;
             esac
 
-            if [ ! -z "${EXIM_CERTIFICATE}" ]; then
+            if [ -n "${EXIM_CERTIFICATE}" ]; then
                 LogText "Result: ${EXIM_CERTIFICATE}"
                 if [ -f "${EXIM_CERTIFICATE}" ]; then
                     Display --indent 4 --text "- Certificate" --result "${STATUS_FOUND}" --color GREEN
@@ -148,7 +148,7 @@
                 Display --indent 4 --text "- Certificate not set" --result "${STATUS_WARNING}" --color WHITE
             fi
 
-            if [ ! -z "${EXIM_PRIVATEKEY}" ]; then
+            if [ -n "${EXIM_PRIVATEKEY}" ]; then
                 LogText "Result: ${EXIM_PRIVATEKEY}"
                 if [ -f "${EXIM_PRIVATEKEY}" ]; then
                     LogText "Result: Private Key found."
@@ -175,7 +175,7 @@
         LogText "Test: check Postfix status"
         # Some other processes also use master, therefore it should include both master and postfix
         FIND1=$(${PSBINARY} ax | ${GREPBINARY} "master" | ${GREPBINARY} "postfix" | ${GREPBINARY} -v "grep")
-        if [ ! -z "${FIND1}" ]; then
+        if [ -n "${FIND1}" ]; then
             LogText "Result: found running Postfix process"
             Display --indent 2 --text "- Postfix status" --result "${STATUS_RUNNING}" --color GREEN
             POSTFIX_RUNNING=1
@@ -210,7 +210,7 @@
     if [ ${SKIPTEST} -eq 0  ]; then
         LogText "Test: using postconf to see if Postfix configuration has errors"
         FIND=$(${POSTCONFBINARY} 2>&1 | ${GREPBINARY} "warning:")
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             Report "postfix_config_error=1"
             Display --indent 6 --text "- Postfix configuration errors" --result "${STATUS_WARNING}" --color RED
             LogText "Result: found an error or warning in the Postfix configuration. Manual check suggested."
@@ -233,21 +233,21 @@
         FIND2=$(${POSTCONFBINARY} 2> /dev/null | ${GREPBINARY} '^smtpd_banner' | ${GREPBINARY} '$mail_name')
         FIND3=$(${POSTCONFBINARY} 2> /dev/null | ${GREPBINARY} '^mail_name' | ${GREPBINARY} -i 'postfix')
         FIND4=$(${POSTCONFBINARY} 2> /dev/null | ${GREPBINARY} '^smtpd_banner' | ${GREPBINARY} -i "${OS}")
-        if [ ! -z "${LINUX_VERSION}" ]; then
+        if [ -n "${LINUX_VERSION}" ]; then
             FIND5=$(${POSTCONFBINARY} 2> /dev/null | ${GREPBINARY} '^smtpd_banner' | ${GREPBINARY} -i "${LINUX_VERSION}")
         fi
         SHOWWARNING=0
 
-        if [ ! -z "${FIND1}" ]; then
+        if [ -n "${FIND1}" ]; then
             SHOWWARNING=1
             Report "banner_software_disclosure[]=${FIND1}"
-        elif [ ! -z "${FIND2}" -a ! -z "${FIND3}" ]; then
+        elif [ -n "${FIND2}" -a -n "${FIND3}" ]; then
             SHOWWARNING=1
             Report "banner_software_disclosure[]=${FIND2}"
-        elif [ ! -z "${FIND4}" ]; then
+        elif [ -n "${FIND4}" ]; then
             SHOWWARNING=1
             Report "banner_os_disclosure[]=${FIND4}"
-        elif [ ! -z "${FIND5}" ]; then
+        elif [ -n "${FIND5}" ]; then
             SHOWWARNING=1
             Report "banner_os_disclosure[]=${FIND5}"
         fi
@@ -342,7 +342,7 @@
 #
     # Test        : MAIL-8920
     # Description : Check OpenSMTPD process status
-    if [ ! -z "${SMTPCTLBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${SMTPCTLBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no MAIL-8920 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check OpenSMTPD status"
     if [ ${SKIPTEST} -eq 0  ]; then
         LogText "Test: check smtpd status"
diff --git a/include/tests_malware b/include/tests_malware
index 340224ce..19172ca6 100644
--- a/include/tests_malware
+++ b/include/tests_malware
@@ -45,7 +45,7 @@
     Register --test-no MALW-3275 --weight L --network NO --category security --description "Check for chkrootkit"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: checking presence chkrootkit"
-        if [ ! -z "${CHKROOTKITBINARY}" ]; then
+        if [ -n "${CHKROOTKITBINARY}" ]; then
             Display --indent 2 --text "- ${GEN_CHECKING} chkrootkit" --result "${STATUS_FOUND}" --color GREEN
             LogText "Result: Found ${CHKROOTKITBINARY}"
             MALWARE_SCANNER_INSTALLED=1
@@ -63,7 +63,7 @@
     Register --test-no MALW-3276 --weight L --network NO --category security --description "Check for Rootkit Hunter"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: checking presence Rootkit Hunter"
-        if [ ! -z "${RKHUNTERBINARY}" ]; then
+        if [ -n "${RKHUNTERBINARY}" ]; then
             Display --indent 2 --text "- ${GEN_CHECKING} Rootkit Hunter" --result "${STATUS_FOUND}" --color GREEN
             LogText "Result: Found ${RKHUNTERBINARY}"
             MALWARE_SCANNER_INSTALLED=1
@@ -307,7 +307,7 @@
     Register --test-no MALW-3288 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check for ClamXav"
     if [ ${SKIPTEST} -eq 0 ]; then
         CLAMSCANBINARY=$(${LSBINARY} /Applications/ClamXav.app/Contents/Resources/ScanningEngine/bin/ 2> /dev/null | ${GREPBINARY} 'clamscan')
-        if [ ! -z "${CLAMSCANBINARY}" ]; then
+        if [ -n "${CLAMSCANBINARY}" ]; then
             LogText "Result: Found ClamXav clamscan installed"
             Display --indent 2 --text "- ${GEN_CHECKING} ClamXav AV scanner" --result "${STATUS_FOUND}" --color GREEN
             MALWARE_SCANNER_INSTALLED=1
diff --git a/include/tests_nameservices b/include/tests_nameservices
index 2ae503e3..4b4b1ac8 100644
--- a/include/tests_nameservices
+++ b/include/tests_nameservices
@@ -188,7 +188,7 @@
 
         # If files and commands can't be found, use defined value from resolv.conf
         if [ -z "${DOMAINNAME}" ]; then
-            if [ ! -z "${RESOLV_DOMAINNAME}" ]; then
+            if [ -n "${RESOLV_DOMAINNAME}" ]; then
                 LogText "Result: using domain name from ${ROOTDIR}etc/resolv.conf"
                 DOMAINNAME=${RESOLV_DOMAINNAME}
             else
@@ -197,7 +197,7 @@
             fi
         fi
 
-        if [ ! -z "${DOMAINNAME}" ]; then
+        if [ -n "${DOMAINNAME}" ]; then
             LogText "Result: found domain name"
             Report "domainname=${DOMAINNAME}"
             Display --indent 2 --text "- Searching DNS domain name" --result "${STATUS_FOUND}" --color GREEN
@@ -303,7 +303,7 @@
                 LogText "Result: found configuration file (${BIND_CONFIG_LOCATION})"
             fi
         done
-        if [ ! -z "${BIND_CONFIG_LOCATION}" ]; then
+        if [ -n "${BIND_CONFIG_LOCATION}" ]; then
             Display --indent 4 --text "- Checking BIND configuration file" --result "${STATUS_FOUND}" --color GREEN
         else
             Display --indent 4 --text "- Checking BIND configuration file" --result "${STATUS_NOT_FOUND}" --color YELLOW
@@ -449,12 +449,12 @@
 #
     # Test        : NAME-4238
     # Description : Check PowerDNS authoritative status
-    if [ ${POWERDNS_RUNNING} -eq 1 -a ! -z "${POWERDNS_AUTH_CONFIG_LOCATION}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ${POWERDNS_RUNNING} -eq 1 -a -n "${POWERDNS_AUTH_CONFIG_LOCATION}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no NAME-4238 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check PowerDNS authoritative status"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking for PowerDNS master status"
         FIND=$(${GREPBINARY} "^master=yes" ${POWERDNS_AUTH_CONFIG_LOCATION})
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             LogText "Found master=yes in configuration file"
             Display --indent 4 --text "- PowerDNS authoritative master: YES"
             POWERDNS_AUTH_MASTER=1
@@ -464,7 +464,7 @@
         fi
         LogText "Test: Checking for PowerDNS slave status"
         FIND=$(${GREPBINARY} "^slave=yes" ${POWERDNS_AUTH_CONFIG_LOCATION})
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             LogText "Found slave=yes in configuration file"
             Display --indent 4 --text "- PowerDNS authoritative slave: YES"
             POWERDNS_AUTH_SLAVE=1
@@ -509,7 +509,7 @@
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking $(domainname) for NIS domain value"
         FIND=$(${DOMAINNAMEBINARY} | ${GREPBINARY} -v "(none)")
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             LogText "Value: ${FIND}"
             NISDOMAIN="${FIND}"
         else
@@ -520,7 +520,7 @@
         if [ -f ${ROOTDIR}etc/defaultdomain ]; then
             LogText "Result: file ${ROOTDIR}etc/defaultdomain exists"
             FIND2=$(cat ${ROOTDIR}etc/defaultdomain)
-            if [ ! -z "${FIND2}" ]; then
+            if [ -n "${FIND2}" ]; then
                 LogText "Output: ${FIND2}"
                 NISDOMAIN="${FIND2}"
             else
@@ -533,7 +533,7 @@
             LogText "Result: file ${ROOTDIR}etc/sysconfig/network exists"
             LogText "Test: checking NISDOMAIN value in file"
             FIND3=$(${GREPBINARY} "^NISDOMAIN" ${ROOTDIR}etc/sysconfig/network | ${AWKBINARY} -F= '{ print $2 }' | ${SEDBINARY} 's/"//g')
-            if [ ! -z "${FIND3}" ]; then
+            if [ -n "${FIND3}" ]; then
                 LogText "Found NIS domain: ${FIND3}"
                 NISDOMAIN="${FIND3}"
             else
@@ -553,7 +553,7 @@
             fi
         fi
         # Check if we found any NIS domain
-        if [ ! -z "${NISDOMAIN}" ]; then
+        if [ -n "${NISDOMAIN}" ]; then
             LogText "Found NIS domain: ${NISDOMAIN}"
             Report "nisdomain=${NISDOMAIN}"
             Display --indent 4 --text "- Checking NIS domain" --result "${STATUS_FOUND}" --color GREEN
@@ -636,7 +636,7 @@
 #
     # Test        : NAME-4408
     # Description : Check localhost entry
-    if [ ! -z "${GETENT_BINARY}" ]; then PREQS_MET="YES"; SKIPREASON="No getent binary"; else PREQS_MET="NO"; SKIPREASON=""; fi
+    if [ -n "${GETENT_BINARY}" ]; then PREQS_MET="YES"; SKIPREASON="No getent binary"; else PREQS_MET="NO"; SKIPREASON=""; fi
     Register --test-no NAME-4408 --preqs-met ${PREQS_MET} --skip-reason "${SKIPREASON}" --weight L --network NO --category security --description "Check localhost entry"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Check server hostname not locally mapped in /etc/hosts"
diff --git a/include/tests_networking b/include/tests_networking
index 8c895c4e..23067c57 100644
--- a/include/tests_networking
+++ b/include/tests_networking
@@ -47,7 +47,7 @@
         IPV6_MISCONFIGURED=0
         IPV6_MISCONFIGURED_MTU=0
         FIND=$(sysctl -a 2> /dev/null | ${GREPBINARY} "^net.ipv6" | ${SEDBINARY} "s/ = /=/")
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             IPV6_CONFIGURED=1
             for I in ${FIND}; do
                 SYSCTL_KEY=$(echo ${I} | ${AWKBINARY} -F= '{ print $1 }')
@@ -124,7 +124,7 @@
         if [ -f /etc/resolv.conf ]; then
             LogText "Result: Found /etc/resolv.conf file"
             FIND=$(${GREPBINARY} '^nameserver' /etc/resolv.conf | ${TRBINARY} -d '\t' | ${SEDBINARY} 's/nameserver*//g' | uniq | ${CUTBINARY} -d# -f1)
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 Display --indent 4 --text "- Testing nameservers"
                 LogText "Test: Querying nameservers"
                 for I in ${FIND}; do
@@ -134,7 +134,7 @@
                     if [ "${I}" = "::1" -o "${I}" = "127.0.0.1" -o "${I}" = "127.0.0.53" -o "${I}" = "127.0.1.1" -o "${I}" = "0.0.0.0" ]; then
                         LOCAL_DNSRESOLVER_FOUND=1
                     fi
-                    if [ ! -z "${DIGBINARY}" ]; then
+                    if [ -n "${DIGBINARY}" ]; then
                         # See if we can query something at the nameserver
                         # 0=good, other=bad
                         DNSRESPONSE=$(${DIGBINARY} +noall +time=3 +retry=0 @${I} ${FQDN} > /dev/null ; echo $?)
@@ -167,7 +167,7 @@
     Register --test-no NETW-2705 --preqs-met ${PREQS_MET} --weight L --network YES --category security --description "Check availability two nameservers"
     if [ ${SKIPTEST} -eq 0 ]; then
         SKIP=0
-        if [ ! -z "${DIGBINARY}" ]; then
+        if [ -n "${DIGBINARY}" ]; then
             if [ ${NUMBERACTIVENS} -lt 2 ]; then
                 Display --indent 4 --text "- Minimal of 2 responsive nameservers" --result "${STATUS_WARNING}" --color RED
                 LogText "Result: less than 2 responsive nameservers found"
@@ -193,12 +193,12 @@
     # Test        : NETW-3001
     # Description : Find default gateway (route)
     # More info   : BSD: ^default   Linux: 0.0.0.0
-    if [ ! -z "${NETSTATBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${NETSTATBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no NETW-3001 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Find default gateway (route)"
     if [ $SKIPTEST -eq 0 ]; then
         LogText "Test: Searching default gateway(s)"
         FIND=$(${NETSTATBINARY} -rn | ${EGREPBINARY} "^0.0.0.0|default" | ${TRBINARY} -s ' ' | ${CUTBINARY} -d ' ' -f2)
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             for I in ${FIND}; do
                 LogText "Result: Found default gateway ${I}"
                 Report "default_gateway[]=${I}"
@@ -222,9 +222,9 @@
                 FIND=$(${IFCONFIGBINARY} -a 2> /dev/null | ${GREPBINARY} "flags=" | ${AWKBINARY} -F ":" '{ print  $1 }')
             ;;
             Linux)
-                if [ ! -z "${IPBINARY}" ]; then
+                if [ -n "${IPBINARY}" ]; then
                     FIND=$(${IPBINARY} link show 2> /dev/null | ${GREPBINARY} "^[0-9]" | ${AWKBINARY} '{ print $2 }' | ${SEDBINARY} 's/://g')
-                elif [ ! -z "${IFCONFIGBINARY}" ]; then
+                elif [ -n "${IFCONFIGBINARY}" ]; then
                     FIND=$(${IFCONFIGBINARY} -a 2> /dev/null | ${AWKBINARY} '{ if ( $2 == "Link" ) { print  $1 }}')
                 fi
             ;;
@@ -265,14 +265,14 @@
                 FIND=$(${IFCONFIGBINARY} -a 2> /dev/null | ${AWKBINARY} '{ if ($1=="ether") print $2 }' | ${SORTBINARY} -u)
                 ;;
             Linux)
-                if [ ! -z "${IFCONFIGBINARY}" ]; then
+                if [ -n "${IFCONFIGBINARY}" ]; then
                     FIND=$(${IFCONFIGBINARY} -a 2> /dev/null | ${GREPBINARY} "HWaddr" | ${AWKBINARY} '{ if ($4=="HWaddr") print $5 }' | ${SORTBINARY} -u)
                     # CentOS 7.x and others may return nothing. Let's retry with 'ether' field.
                     if [ -z "${FIND}" ]; then
                         FIND=$(${IFCONFIGBINARY} -a 2> /dev/null | ${AWKBINARY} '{ if ($1=="ether") print $2 }' | ${SORTBINARY} -u)
                     fi
                 else
-                    if [ ! -z "${IPBINARY}" ]; then
+                    if [ -n "${IPBINARY}" ]; then
                         LogText "Test: Using ip binary to gather hardware addresses"
                         FIND=$(${IPBINARY} link 2> /dev/null | ${GREPBINARY} "link/ether" | ${AWKBINARY} '{ print $2 }')
                     else
@@ -320,12 +320,12 @@
                 FIND2=$(${IFCONFIGBINARY} -a 2> /dev/null | ${AWKBINARY} '{ if ($1=="inet6") print $2 }')
                 ;;
             Linux)
-                if [ ! -z "${IFCONFIGBINARY}" ]; then
+                if [ -n "${IFCONFIGBINARY}" ]; then
                     FIND=$(${IFCONFIGBINARY} -a 2> /dev/null | ${AWKBINARY} '{ if ($1=="inet") print $2 }' | ${CUTBINARY} -d ':' -f2)
                     # Version which works for multiple types of ifconfig (e.g. Slackware)
                     FIND2=$(${IFCONFIGBINARY} -a 2> /dev/null | ${AWKBINARY} '{ if ($1=="inet6" && $2=="addr:") { print $3 } else { if ($1=="inet6" && $3=="prefixlen") { print $2 } } }')
                 else
-                    if [ ! -z "${IPBINARY}" ]; then
+                    if [ -n "${IPBINARY}" ]; then
                         LogText "Test: Using ip binary to gather IP addresses"
                         FIND=$(${IPBINARY} addr 2> /dev/null | ${AWKBINARY} '{ if ($1=="inet") { print $2 }}' | ${SEDBINARY} 's/\/.*//')
                         FIND2=$(${IPBINARY} addr 2> /dev/null | ${AWKBINARY} '{ if ($1=="inet6") { print $2 }}' | ${SEDBINARY} 's/\/.*//')
@@ -375,7 +375,7 @@
         COUNT=0
         case ${OS} in
             DragonFly|FreeBSD)
-                if [ ! -z "${SOCKSTATBINARY}" ]; then
+                if [ -n "${SOCKSTATBINARY}" ]; then
                     FIND=$(${SOCKSTATBINARY} | ${AWKBINARY} '{ if ($7 ~ /\*:\*/) print $5"|"$6"|"$2"|" }' | ${SORTBINARY} -u)
                     # To strip off IP's: ${SEDBINARY} 's/|.*:/|/'
                 else
@@ -513,17 +513,17 @@
         NETWORK=""
         USE_IP_INSTEAD_IFCONFIG=0
 
-        if [ ! -z "${IPBINARY}" ]; then
+        if [ -n "${IPBINARY}" ]; then
             LogText "Test: Using ip binary to retrieve network interfaces"
             NETWORK=$(${IPBINARY} -o link 2> /dev/null | ${GREPBINARY} "^[0-9]" | ${AWKBINARY} '{print $2 }' | ${TRBINARY} -d ':')
             USE_IP_INSTEAD_IFCONFIG=1
-        elif [ ! -z "${IFCONFIGBINARY}" ]; then
+        elif [ -n "${IFCONFIGBINARY}" ]; then
             LogText "Test: Using ifconfig binary to retrieve network interfaces"
             NETWORK=$(${IFCONFIGBINARY} 2> /dev/null | ${GREPBINARY} Link | ${TRBINARY} -s ' ' | ${CUTBINARY} -d ' ' -f1)
         fi
 
         LogText "Test: Checking all interfaces to discover any with promiscuous mode enabled"
-        if [ ! -z "${NETWORK}" ]; then
+        if [ -n "${NETWORK}" ]; then
             FOUNDPROMISC=0
             for I in ${NETWORK}; do
                 if [ ${USE_IP_INSTEAD_IFCONFIG} -eq 1 ]; then
@@ -531,7 +531,7 @@
                 else
                     FIND=$(${IFCONFIGBINARY} ${I} 2> /dev/null | ${GREPBINARY} PROMISC)
                 fi
-                if [ ! -z "${FIND}" ]; then
+                if [ -n "${FIND}" ]; then
                     LogText "Result: Promiscuous interface: ${I}"
                     ISWHITELISTED=$(${GREPBINARY} "^if_promisc:${I}:" ${PROFILE})
                     if [ -z "${ISWHITELISTED}" ]; then
diff --git a/include/tests_php b/include/tests_php
index 76606c64..ef43f282 100644
--- a/include/tests_php
+++ b/include/tests_php
@@ -139,7 +139,7 @@
             fi
         done
 
-        if [ ! -z "${PHPINIFILE}" ]; then
+        if [ -n "${PHPINIFILE}" ]; then
             Display --indent 2 --text "- Checking PHP" --result "${STATUS_FOUND}" --color GREEN
             LogText "Result: using single file ${PHPINIFILE} for main php.ini tests"
             LogText "Result: using php.ini array ${PHPINI_ALLFILES} for further tests"
@@ -154,7 +154,7 @@
 #
     # Test        : PHP-2320
     # Description : Check php disable functions option
-    if [ ! -z "${PHPINI_ALLFILES}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${PHPINI_ALLFILES}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no PHP-2320 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check PHP disabled functions"
     if [ ${SKIPTEST} -eq 0 ]; then
         FOUND=0
@@ -194,7 +194,7 @@
     # Test        : PHP-2368
     # Description : Check php register_globals option
     # Notes       : Don't test for it if PHP version is 5.4.0 or later (it has been removed)
-    if [ ! -z "${PHPINIFILE}" -a ! -z "${PHPVERSION}" -a ! -z "${EGREPBINARY}" ]; then
+    if [ -n "${PHPINIFILE}" -a -n "${PHPVERSION}" -a -n "${EGREPBINARY}" ]; then
         if [ -f "${PHPINIFILE}" ]; then
             FIND=$(echo ${PHPVERSION} | ${EGREPBINARY} "^(4.|5.[0-3])")
             if [ -z "${FIND}" ]; then
@@ -215,7 +215,7 @@
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking PHP register_globals option"
         FIND=$(${EGREPBINARY} -i 'register_globals.*(on|yes|1)' ${PHPINIFILE} | ${GREPBINARY} -v '^;')
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             Display --indent 4 --text "- Checking register_globals option" --result "${STATUS_WARNING}" --color RED
             ReportWarning ${TEST_NO} "PHP option register_globals option is turned on, which can be a risk for variable value overwriting"
             ReportSuggestion ${TEST_NO} "Change the register_globals line to: register_globals = Off"
@@ -235,7 +235,7 @@
     # Description : Check PHP expose_php option
     # Background  : When this option is turned on, PHP will show its version number in the HTTP headers
     # Notes       : TODO - Extend test to check all PHP files
-    if [ ! -z "${PHPINI_ALLFILES}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${PHPINI_ALLFILES}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no PHP-2372 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check PHP expose_php option"
     if [ ${SKIPTEST} -eq 0 ]; then
         FOUND=0
@@ -266,12 +266,12 @@
     # Test        : PHP-2374
     # Description : Check PHP enable_dl option
     # Notes       : Extend test to check all PHP files
-    if [ ! -z "${PHPINIFILE}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${PHPINIFILE}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no PHP-2374 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check PHP enable_dl option"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking PHP enable_dl option"
         FIND=$(${EGREPBINARY} -i 'enable_dl.*(on|yes|1)' ${PHPINIFILE} | ${GREPBINARY} -v '^;')
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             Display --indent 4 --text "- Checking enable_dl option" --result "${STATUS_ON}" --color YELLOW
             Report "Result: enable_dl option is turned on, which can be used to enable more modules dynamically and circumventing security controls"
             ReportSuggestion ${TEST_NO} "Change the enable_dl line to: enable_dl = Off, to disable dynamically loading new modules"
@@ -288,7 +288,7 @@
     # Test        : PHP-2376
     # Description : Check PHP allow_url_fopen option
     # Notes       : Extend test to check all PHP files YYY
-    if [ ! -z "${PHPINIFILE}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${PHPINIFILE}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no PHP-2376 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check PHP allow_url_fopen option"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking PHP allow_url_fopen option"
@@ -311,7 +311,7 @@
     # Test        : PHP-2378
     # Description : Check PHP allow_url_include option
     # Notes       : Extend test to check all PHP files YYY
-    if [ ! -z "${PHPINIFILE}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${PHPINIFILE}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no PHP-2378 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check PHP allow_url_include option"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking PHP allow_url_include option"
@@ -333,7 +333,7 @@
     # - test disabled for time being, as newer suhosin7 work is not stable enough -
     # Test        : PHP-2379
     # Description : Check PHP suhosin extension status
-    #if [ ! -z "${PHPINI_ALLFILES}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    #if [ -n "${PHPINI_ALLFILES}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     #Register --test-no PHP-2379 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check PHP suhosin extension status"
 
     #if [ ${SKIPTEST} -eq 0 ]; then
@@ -365,14 +365,14 @@
     #    fi
 
     #    # Check Suhosin for PHP 7
-    #    if [ ! -z "${MAJOR_VERSION}" -a ${FOUND} -eq 1 ]; then
+    #    if [ -n "${MAJOR_VERSION}" -a ${FOUND} -eq 1 ]; then
     #        LogText "Test: Check Suhosin for PHP 7 is not enabled"
     #        LogText "Result: Suhosin for PHP 7 is in alpha stage and should not be used in production"
     #        ReportSuggestion ${TEST_NO} "Disable Suhosin for PHP 7"
     #        Display --indent 4 --text "- Checking PHP suhosin extension status" --result "${STATUS_WARNING}" --color RED
     #        Display --indent 6 --text "- Suhosin is enabled for PHP 7" --result "${STATUS_WARNING}" --color RED
     #        AddHP 0 1
-    #    elif [ ! -z "${MAJOR_VERSION}" -a ${FOUND} -eq 0 ]; then
+    #    elif [ -n "${MAJOR_VERSION}" -a ${FOUND} -eq 0 ]; then
     #        LogText "Test: Check Suhosin for PHP 7 is not enabled"
     #        LogText "Result: Suhosin for PHP 7 is not enabled"
     #        Display --indent 4 --text "- Checking PHP suhosin extension status" --result "${STATUS_OK}" --color GREEN
diff --git a/include/tests_ports_packages b/include/tests_ports_packages
index 6b6b2ed9..e82c8eaf 100644
--- a/include/tests_ports_packages
+++ b/include/tests_ports_packages
@@ -88,7 +88,7 @@
     # Test        : PKGS-7303
     # Description : Query brew package manager
     FIND=$(which brew 2> /dev/null | grep -v "no [^ ]* in ")
-    if [ ! -z "${FIND}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${FIND}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no PKGS-7303 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Query brew package manager"
     if [ ${SKIPTEST} -eq 0 ]; then
         Display --indent 4 --text "- Searching brew" --result "${STATUS_FOUND}" --color GREEN
@@ -158,7 +158,7 @@
 #
     # Test        : PKGS-7308
     # Description : RPM package based systems
-    if [ ! -z "${RPMBINARY}" -a -z "${DNFBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${RPMBINARY}" -a -z "${DNFBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no PKGS-7308 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Checking package list with RPM"
     if [ ${SKIPTEST} -eq 0 ]; then
         COUNT=0
@@ -191,7 +191,7 @@
 #
     # Test        : PKGS-7310
     # Description : pacman package based systems
-    if [ ! -z "${PACMANBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${PACMANBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no PKGS-7310 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Checking package list with pacman"
     if [ ${SKIPTEST} -eq 0 ]; then
         COUNT=0
@@ -222,12 +222,12 @@
 #
     # Test        : PKGS-7312
     # Description : Check for available package updates when pacman package is used
-    if [ ! -z "${PACMANBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${PACMANBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no PKGS-7312 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Checking available updates for pacman based system"
     if [ ${SKIPTEST} -eq 0 ]; then
         FOUND=0
         FIND=$(which checkupdates 2> /dev/null | grep -v "no [^ ]* in ")
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             FIND=$(checkupdates)
             for I in ${FIND}; do
                 LogText "Result: update available for ${I}"
@@ -252,7 +252,7 @@
     # Test        : PKGS-7314
     # Description : Check pacman.conf options
     PACMANCONF="/etc/pacman.conf"
-    if [ ! -z "${PACMANBINARY}" -a -f ${PACMANCONF} ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${PACMANBINARY}" -a -f ${PACMANCONF} ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no PKGS-7314 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Checking pacman configuration options"
     if [ ${SKIPTEST} -eq 0 ]; then
         COUNT=0
@@ -315,7 +315,7 @@
 #
     # Test        : PKGS-7322
     # Description : Discover vulnerable packages with arch-audit
-    if [ ! -z "${ARCH_AUDIT_BINARY}" ]; then PREQS_MET="YES"; SKIPREASON=""; else PREQS_MET="NO"; SKIPREASON="arch-audit not found"; fi
+    if [ -n "${ARCH_AUDIT_BINARY}" ]; then PREQS_MET="YES"; SKIPREASON=""; else PREQS_MET="NO"; SKIPREASON="arch-audit not found"; fi
     Register --test-no PKGS-7322 --os "Linux" --preqs-met ${PREQS_MET} --skip-reason "${SKIPREASON}" --weight L --network NO --category security --description "Discover vulnerable packages with arch-audit"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: checking arch-audit output for vulnerable packages"
@@ -338,14 +338,14 @@
 #
     # Test        : PKGS-7328
     # Description : Check installed packages with Zypper
-    if [ ! -z "${ZYPPERBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${ZYPPERBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no PKGS-7328 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Querying Zypper for installed packages"
     if [ ${SKIPTEST} -eq 0 ]; then
         COUNT=0
         PACKAGE_AUDIT_TOOL_FOUND=1
         PACKAGE_AUDIT_TOOL="zypper"
         FIND=$(${ZYPPERBINARY} --non-interactive -n se -t package -i | ${AWKBINARY} '{ if ($1=="i") { print $3 } }')
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             for PKG in ${FIND}; do
                 COUNT=$((COUNT + 1))
                 LogText "Installed package: ${PKG}"
@@ -362,11 +362,11 @@
 #
     # Test        : PKGS-7330
     # Description : Check vulnerable packages with Zypper
-    if [ ! -z "${ZYPPERBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${ZYPPERBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no PKGS-7330 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Querying Zypper for vulnerable packages"
     if [ ${SKIPTEST} -eq 0 ]; then
         FIND=$(${ZYPPERBINARY} --non-interactive pchk | ${GREPBINARY} "(0 security patches)")
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             LogText "Result: No security updates found with Zypper"
             Display --indent 2 --text "- Using Zypper to find vulnerable packages" --result "${STATUS_NONE}" --color GREEN
         else
@@ -520,7 +520,7 @@
     # Test        : PKGS-7350
     # Description : Use Dandified YUM to gather installed packages
     # Notes       : Possible replacement for YUM in the long term
-    if [ ! -z "${DNFBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${DNFBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no "PKGS-7350" --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Checking for installed packages with DNF utility"
     if [ ${SKIPTEST} -eq 0 ]; then
         COUNT=0
@@ -546,13 +546,13 @@
 #
     # Test        : PKGS-7352
     # Description : Use Dandified YUM to detect security updates
-    if [ ! -z "${DNFBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${DNFBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no "PKGS-7352" --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Checking for security updates with DNF utility"
     if [ ${SKIPTEST} -eq 0 ]; then
         # Check for security updates
         LogText "Action: checking updateinfo for security updates"
         FIND=$(${DNFBINARY} -q updateinfo list sec 2> /dev/null | ${AWKBINARY} '{ if ($2=="security") { print $3 }}')
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             VULNERABLE_PACKAGES_FOUND=1
             LogText "Result: found vulnerable packages, upgrade of system needed."
             for PKG in ${FIND}; do
@@ -574,20 +574,20 @@
 #
     # Test        : PKGS-7354
     # Description : Perform integrity tests for package database
-    if [ ! -z "${DNFBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${DNFBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no "PKGS-7354" --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Checking package database integrity"
     if [ ${SKIPTEST} -eq 0 ]; then
         # Check if repoquery plugin is available
         FIND=$(${DNFBINARY} 2>&1 | ${GREPBINARY} "^repoquery")
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             LogText "Action: checking integrity of package database"
             FIND=$(${DNFBINARY} -q repoquery --duplicated)
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 LogText "Result: found unexpected result on repoquery --duplicated"
                 ReportSuggestion "${TEST_NO}" "Check output of: dnf repoquery --duplicated"
             fi
             FIND=$(${DNFBINARY} -q repoquery --unsatisfied)
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 LogText "Result: found unexpected result on repoquery --unsatisfied"
                 ReportSuggestion "${TEST_NO}" "Check output of: dnf repoquery --unsatisfied"
             fi
@@ -600,17 +600,17 @@
 #
     # Test        : PKGS-7366
     # Description : Checking if debsecan is installed and enabled on Debian systems
-    if [ ! -z "${DEBSECANBINARY}" -a "${OS}" = "Linux" -a "${LINUX_VERSION}" = "Debian" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${DEBSECANBINARY}" -a "${OS}" = "Linux" -a "${LINUX_VERSION}" = "Debian" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no "PKGS-7366" --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Checking for debsecan utility"
     if [ ${SKIPTEST} -eq 0 ]; then
-        if [ ! -z "${DEBSECANBINARY}" ]; then
+        if [ -n "${DEBSECANBINARY}" ]; then
             LogText "Result: debsecan utility is installed"
             Display --indent 4 --text "- debsecan utility" --result "${STATUS_FOUND}" --color GREEN
             AddHP 3 3
             PACKAGE_AUDIT_TOOL_FOUND=1
             PACKAGE_AUDIT_TOOL="debsecan"
             FIND=$(${FINDBINARY} ${ROOTDIR}etc/cron* -name debsecan)
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 LogText "Result: cron job is configured for debsecan"
                 Display --indent 6 --text "- debsecan cron job" --result "${STATUS_FOUND}" --color GREEN
                 AddHP 3 3
@@ -633,10 +633,10 @@
     # Test        : PKGS-7370
     # Description : Checking debsums installation status and presence in cron job
     # Note        : Run this only when it is a DPKG based system
-    if [ ! -z "${DPKGBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${DPKGBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no "PKGS-7370" --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Checking for debsums utility"
     if [ ${SKIPTEST} -eq 0 ]; then
-        if [ ! -z "${DEBSUMSBINARY}" ]; then
+        if [ -n "${DEBSUMSBINARY}" ]; then
             LogText "Result: debsums utility is installed"
             Display --indent 4 --text "- debsums utility" --result "${STATUS_FOUND}" --color GREEN
             AddHP 1 1
@@ -728,7 +728,7 @@
     # Description : Check for vulnerable FreeBSD packages (with pkg)
     # Notes       : Related vulnerability file is /var/db/pkg/vuln.xml
     # TODO        : Run this in any jail
-    if [ ! -z "${PKG_BINARY}" ]; then PREQS_MET="YES"; SKIPREASON=""; else PREQS_MET="NO"; SKIPREASON="pkg tool not available"; fi
+    if [ -n "${PKG_BINARY}" ]; then PREQS_MET="YES"; SKIPREASON=""; else PREQS_MET="NO"; SKIPREASON="pkg tool not available"; fi
     Register --test-no PKGS-7381 --preqs-met ${PREQS_MET} --skip-reason "${SKIPREASON}" --weight L --network NO --category security --description "Check for vulnerable FreeBSD packages with pkg"
     if [ ${SKIPTEST} -eq 0 ]; then
         COUNT=0
@@ -746,7 +746,7 @@
                 Display --indent 2 --text "- Checking pkg audit to obtain vulnerable packages" --result "${STATUS_NONE}" --color GREEN
                 AddHP 10 10
             elif [ $? -eq 1 ]; then
-                if [ ! -z "${FIND}" ]; then
+                if [ -n "${FIND}" ]; then
                     VULNERABLE_PACKAGES_FOUND=1
                     Display --indent 2 --text "- Checking pkg audit to obtain vulnerable packages" --result "${STATUS_FOUND}" --color YELLOW
                     for ITEM in ${FIND}; do
@@ -804,7 +804,7 @@
     # Test        : PKGS-7383
     # Description : Check for YUM package Update management
     # Notes       : Skip if DNF is used as package manager
-    if [ ! -z "${YUMBINARY}" -a -z "${DNFBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${YUMBINARY}" -a -z "${DNFBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no PKGS-7383 --preqs-met ${PREQS_MET} --os Linux --weight M --network NO --category security --description "Check for YUM package update management"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: YUM package update management"
@@ -823,7 +823,7 @@
 #
     # Test        : PKGS-7384
     # Description : Search for YUM utils package
-    if [ ! -z "${YUMBINARY}" -a -z "${DNFBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${YUMBINARY}" -a -z "${DNFBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no PKGS-7384 --preqs-met ${PREQS_MET} --os Linux --weight L --network NO --category security --description "Check for YUM utils package"
     if [ ${SKIPTEST} -eq 0 ]; then
         # package-cleanup tool can be found in different locations
@@ -903,7 +903,7 @@
         # Check if it's installed as package (this is old style)
         if [ ${DO_TEST} -eq 0 ]; then
             FIND=$(rpm -q yum-security yum-plugin-security | ${GREPBINARY} -v "not installed")
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 LogText "Result: found yum-plugin-security package"
                 DO_TEST=1
             fi
@@ -943,7 +943,7 @@
     if [ -x ${ROOTDIR}usr/bin/yum -a -z "${DNFBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no PKGS-7387 --preqs-met ${PREQS_MET} --os Linux --weight L --network NO --category security --description "Check for GPG signing in YUM security package"
     if [ ${SKIPTEST} -eq 0 ]; then
-        if [ ! -z "${PYTHONBINARY}" ]; then
+        if [ -n "${PYTHONBINARY}" ]; then
             LogText "Test: checking enabled repositories"
             REPOS=$(${PYTHONBINARY} -c 'import yum ; yb = yum.YumBase() ; yb.conf ; print [(r.id + "=" + str(r.gpgcheck)) for r in yb.repos.listEnabled()]' | ${GREPBINARY} "^\[" | ${TRBINARY} -d '[] ' | ${TRBINARY} -d "'" | ${SEDBINARY} 's/,/ /g')
             if [ -z "${REPOS}" ]; then LogText "Result: found no repositories"; fi
@@ -991,7 +991,7 @@
             if [ -f ${ROOTDIR}etc/apt/sources.list ]; then
                 LogText "Searching for security.debian.org/security.ubuntu.com or security repositories in /etc/apt/sources.list file"
                 FIND=$(${EGREPBINARY} "security.debian.org|security.ubuntu.com|security/? " ${ROOTDIR}etc/apt/sources.list | ${GREPBINARY} -v '#' | ${SEDBINARY} 's/ /!space!/g')
-                if [ ! -z "${FIND}" ]; then
+                if [ -n "${FIND}" ]; then
                     FOUND=1
                     Display --indent 2 --text "- Checking security repository in sources.list file" --result "${STATUS_OK}" --color GREEN
                     LogText "Result: Found security repository in ${ROOTDIR}etc/apt/sources.list"
@@ -1004,7 +1004,7 @@
             if [ -d /etc/apt/sources.list.d ]; then
                 LogText "Searching for security.debian.org/security.ubuntu.com or security repositories in /etc/apt/sources.list.d directory"
                 FIND=$(${EGREPBINARY} -r "security.debian.org|security.ubuntu.com|security/? " /etc/apt/sources.list.d | ${GREPBINARY} -v '#' | ${SEDBINARY} 's/ /!space!/g')
-                if [ ! -z "${FIND}" ]; then
+                if [ -n "${FIND}" ]; then
                     FOUND=1
                     Display --indent 2 --text "- Checking security repository in sources.list.d directory" --result "${STATUS_OK}" --color GREEN
                     LogText "Result: Found security repository in one or more files in directory /etc/apt/sources.list.d"
@@ -1100,7 +1100,7 @@
         # Trying also with apt-get directly (does not always work, as updates are distributed on both -security and -updates)
         # Show packages which would be upgraded and match 'security' in repository name
         FIND=$(${ROOTDIR}usr/bin/apt-get --dry-run --show-upgraded upgrade 2> /dev/null | ${GREPBINARY} '-security' | ${GREPBINARY} "^Inst" | ${CUTBINARY} -d ' ' -f2 | ${SORTBINARY} -u)
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             VULNERABLE_PACKAGES_FOUND=1
             SCAN_PERFORMED=1
             LogText "Result: found vulnerable package(s) via apt-get (-security channel)"
@@ -1247,7 +1247,7 @@
         KERNELS=0
         LogText "Test: Checking how many kernel packages are installed"
 
-        if [ ! -z "${DPKGBINARY}" ]; then
+        if [ -n "${DPKGBINARY}" ]; then
             KERNELS=$(${DPKGBINARY} -l 2> /dev/null | ${GREPBINARY} "linux-image-[0-9]" | ${WCBINARY} -l)
             if [ ${KERNELS} -eq 0 ]; then
                 LogText "Result: found no kernels from dpkg -l output, which is unexpected"
@@ -1258,7 +1258,7 @@
             else
                 LogText "Result: found ${KERNELS} kernel packages on the system, which is fine"
             fi
-        elif [ ! -z "${RPMBINARY}" ]; then
+        elif [ -n "${RPMBINARY}" ]; then
             KERNELS=$(${RPMBINARY} -q kernel 2> /dev/null | ${WCBINARY} -l)
             if [ ${KERNELS} -eq 0 ]; then
                 LogText "Result: found no kernels from rpm -q kernel output, which is unexpected"
diff --git a/include/tests_printers_spools b/include/tests_printers_spools
index 5c492a9e..5786f4c7 100644
--- a/include/tests_printers_spools
+++ b/include/tests_printers_spools
@@ -211,7 +211,7 @@
         FileIsReadable ${QDAEMON_CONFIG_FILE}
         if [ ${CANREAD} -eq 1 ]; then
             FIND=$(${GREPBINARY} -v "^\*" ${QDAEMON_CONFIG_FILE} | ${EGREPBINARY} "backend|device")
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 LogText "Result: printers are defined in ${QDAEMON_CONFIG_FILE}"
                 Display --indent 2 --text "- Checking /etc/qconfig file" --result "${STATUS_FOUND}" --color GREEN
                 QDAEMON_CONFIG_ENABLED=1
@@ -279,7 +279,7 @@
 #################################################################################
 #
 
-if [ ! -z ${PRINTING_DAEMON} ]; then Report "printing_daemon=${PRINTING_DAEMON}"; fi
+if [ -n ${PRINTING_DAEMON} ]; then Report "printing_daemon=${PRINTING_DAEMON}"; fi
 
 WaitForKeyPress
 
diff --git a/include/tests_scheduling b/include/tests_scheduling
index 91a89c63..98b29932 100644
--- a/include/tests_scheduling
+++ b/include/tests_scheduling
@@ -170,7 +170,7 @@
             if [ -f /etc/anacrontab ]; then
                 LogText "Test: checking anacrontab"
                 sANACRONJOBS=$(${EGREPBINARY} '^([0-9@])' /etc/anacrontab | ${TRBINARY} '\t' ' ' | ${TRBINARY} -s ' ' | ${TRBINARY} ' ' ',' | ${SORTBINARY})
-                if [ ! -z "${sANACRONJOBS}" ]; then
+                if [ -n "${sANACRONJOBS}" ]; then
                     Report "scheduler[]=anacron"
                     for I in ${sANACRONJOBS}; do
                         LogText "Found anacron job (/etc/anacrontab): ${I}"
@@ -201,7 +201,7 @@
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking atd status"
         FIND=$(${PSBINARY} ax | ${GREPBINARY} "/atd" | ${GREPBINARY} -v "grep")
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             LogText "Result: at daemon active"
             Display --indent 2 --text "- Checking atd status" --result "${STATUS_RUNNING}" --color GREEN
             ATD_RUNNING=1
diff --git a/include/tests_shells b/include/tests_shells
index 3a094ad8..8e97ae86 100644
--- a/include/tests_shells
+++ b/include/tests_shells
@@ -126,7 +126,7 @@
             FIND=$(${GREPBINARY} 'TMOUT=' ${ROOTDIR}etc/profile | ${TRBINARY} -d ' ' | ${TRBINARY} -d '\t' | ${GREPBINARY} -v "^#" | ${SEDBINARY} 's/export//' | ${SEDBINARY} 's/#.*//' | ${AWKBINARY} -F= '{ print $2 }')
             # Determine if the value is exported (with export, readonly, or typeset)
             FIND2=$(${GREPBINARY} '\(export\|readonly\|typeset -r\)[ \t]*TMOUT' ${ROOTDIR}etc/profile | ${GREPBINARY} -v "^#" | ${SEDBINARY} 's/#.*//' | ${AWKBINARY} '{ print $1 }')
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 N=0; IDLE_TIMEOUT=1
                 for I in ${FIND}; do
                     LogText "Output: ${I}"
@@ -143,7 +143,7 @@
                 LogText "Result: could not find TMOUT setting in ${ROOTDIR}etc/profile"
             fi
 
-            if [ ! -z "${FIND2}" ]; then
+            if [ -n "${FIND2}" ]; then
                 N=0;
                 for I in ${FIND2}; do
                     LogText "Output: ${I}"
@@ -167,12 +167,12 @@
 
         if [ -d ${ROOTDIR}etc/profile.d ]; then
             FIND=$(${LSBINARY} ${ROOTDIR}etc/profile.d/*.sh 2> /dev/null)
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 # Determine if we can find a TMOUT value
                 FIND=$(${FINDBINARY} ${ROOTDIR}etc/profile.d -name "*.sh" -type f -exec cat {} \; 2> /dev/null | ${GREPBINARY} 'TMOUT=' | ${TRBINARY} -d ' ' | ${TRBINARY} -d '\t' | ${GREPBINARY} -v "^#" | ${SEDBINARY} 's/export//' | ${SEDBINARY} 's/#.*//' | ${AWKBINARY} -F= '{ print $2 }')
                 # Determine if the value is exported (with export, readonly, or typeset)
                 FIND2=$(${FINDBINARY} ${ROOTDIR}etc/profile.d -name "*.sh" -type f -exec cat {} \; 2> /dev/null | ${GREPBINARY} '\(export\|readonly\|typeset -r\)[ \t]*TMOUT' | ${GREPBINARY} -v "^#" | ${SEDBINARY} 's/#.*//' | ${AWKBINARY} '{ print $1 }')
-                if [ ! -z "${FIND}" ]; then
+                if [ -n "${FIND}" ]; then
                     N=0; IDLE_TIMEOUT=1
                     for I in ${FIND}; do
                         LogText "Output: ${I}"
@@ -189,7 +189,7 @@
                     LogText "Result: could not find TMOUT setting in ${ROOTDIR}etc/profile.d/*.sh"
                 fi
                 # Check for readonly
-                if [ ! -z "${FIND2}" ]; then
+                if [ -n "${FIND2}" ]; then
                     N=0;
                     for I in ${FIND2}; do
                         LogText "Output: ${I}"
@@ -212,10 +212,10 @@
             LogText "Result: skip ${ROOTDIR}etc/profile.d directory test, directory not available on this system"
         fi
 
-        if [ ! -z "${IDLE_TIMEOUT_METHOD}" ]; then
+        if [ -n "${IDLE_TIMEOUT_METHOD}" ]; then
             Report "session_timeout_method[]=${IDLE_TIMEOUT_METHOD}"
         fi
-        if [ ! -z "${IDLE_TIMEOUT_READONLY}" ]; then
+        if [ -n "${IDLE_TIMEOUT_READONLY}" ]; then
             Report "session_timeout_set_readonly=${IDLE_TIMEOUT_READONLY}"
         fi
 
diff --git a/include/tests_snmp b/include/tests_snmp
index 5140555f..8b82d9e8 100644
--- a/include/tests_snmp
+++ b/include/tests_snmp
@@ -74,7 +74,7 @@
 #
     # Test        : SNMP-3306
     # Description : Determine SNMP communities
-    if [ ! -z "${SNMP_DAEMON_CONFIG}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${SNMP_DAEMON_CONFIG}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no SNMP-3306 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check SNMP communities"
     if [ ${SKIPTEST} -eq 0 ]; then
         WARN=0
diff --git a/include/tests_squid b/include/tests_squid
index c9eb1b71..bfb699f0 100644
--- a/include/tests_squid
+++ b/include/tests_squid
@@ -43,7 +43,7 @@
         FOUND=0
         # Check running processes
         FIND=$(${PSBINARY} ax | ${EGREPBINARY} "(squid|squid3) " | ${GREPBINARY} -v "grep")
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             SQUID_DAEMON_RUNNING=1
             LogText "Result: Squid daemon is running"
             Display --indent 2 --text "- Checking running Squid daemon" --result "${STATUS_FOUND}" --color GREEN
@@ -86,10 +86,10 @@
 #
     # Test        : SQD-3606
     # Description : Check Squid version
-    if [ ${SQUID_DAEMON_RUNNING} -eq 1 -a ! -z "${SQUID_DAEMON_CONFIG}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ${SQUID_DAEMON_RUNNING} -eq 1 -a -n "${SQUID_DAEMON_CONFIG}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no SQD-3606 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check Squid version"
     if [ ${SKIPTEST} -eq 0 ]; then
-        if [ ! -z "${SQUIDBINARY}" ]; then
+        if [ -n "${SQUIDBINARY}" ]; then
             LogText "Result: Squid binary found (${SQUIDBINARY})"
             # Skip check if a setuid/setgid bit is found
             FIND=$(${FINDBINARY} ${SQUIDBINARY} \( -perm 4000 -o -perm 2000 \) -print)
@@ -110,7 +110,7 @@
 #
     # Test        : SQD-3610
     # Description : Check Squid configuration options
-    if [ ${SQUID_DAEMON_RUNNING} -eq 1 -a ! -z "${SQUID_DAEMON_CONFIG}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ${SQUID_DAEMON_RUNNING} -eq 1 -a -n "${SQUID_DAEMON_CONFIG}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no SQD-3610 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Gather Squid settings"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking all specific defined options in ${SQUID_DAEMON_CONFIG}"
@@ -127,12 +127,12 @@
 #
     # Test        : SQD-3613
     # Description : Check Squid configuration file permissions
-    if [ ${SQUID_DAEMON_RUNNING} -eq 1 -a ! -z "${SQUID_DAEMON_CONFIG}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ${SQUID_DAEMON_RUNNING} -eq 1 -a -n "${SQUID_DAEMON_CONFIG}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no SQD-3613 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check Squid file permissions"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking file permissions of ${SQUID_DAEMON_CONFIG}"
         FIND=$(find ${SQUID_DAEMON_CONFIG} -type f -a \( -perm -004 -o -perm -002 -o -perm -001 \))
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             LogText "Result: file ${SQUID_DAEMON_CONFIG} is world readable, writable or executable and could leak information or passwords"
             Display --indent 4 --text "- Checking Squid configuration file permissions" --result "${STATUS_WARNING}" --color RED
             ReportSuggestion ${TEST_NO} "Check file permissions of ${SQUID_DAEMON_CONFIG} to limit access"
@@ -147,7 +147,7 @@
 #
 #################################################################################
 #
-    if [ ${SQUID_DAEMON_RUNNING} -eq 1 -a ! -z "${SQUID_DAEMON_CONFIG}" ]; then
+    if [ ${SQUID_DAEMON_RUNNING} -eq 1 -a -n "${SQUID_DAEMON_CONFIG}" ]; then
         Display --indent 4 --text "- Checking Squid access control"
     fi
 #
@@ -155,7 +155,7 @@
 #
     # Test        : SQD-3614
     # Description : Check Squid authentication
-    if [ ${SQUID_DAEMON_RUNNING} -eq 1 -a ! -z "${SQUID_DAEMON_CONFIG}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ${SQUID_DAEMON_RUNNING} -eq 1 -a -n "${SQUID_DAEMON_CONFIG}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no SQD-3614 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check Squid authentication methods"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: check auth_param option for authentication methods"
@@ -176,7 +176,7 @@
 #
     # Test        : SQD-3616
     # Description : Check external Squid authentication
-    if [ ${SQUID_DAEMON_RUNNING} -eq 1 -a ! -z "${SQUID_DAEMON_CONFIG}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ${SQUID_DAEMON_RUNNING} -eq 1 -a -n "${SQUID_DAEMON_CONFIG}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no SQD-3616 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check external Squid authentication"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: check external_acl_type option for external authentication helpers"
@@ -265,7 +265,7 @@
 #
 #################################################################################
 #
-    if [ ${SQUID_DAEMON_RUNNING} -eq 1 -a ! -z "${SQUID_DAEMON_CONFIG}" ]; then
+    if [ ${SQUID_DAEMON_RUNNING} -eq 1 -a -n "${SQUID_DAEMON_CONFIG}" ]; then
         Display --indent 4 --text "- Checking Squid Denial of Service tuning options"
     fi
 #
@@ -273,7 +273,7 @@
 #
     # Test        : SQD-3630 [T]
     # Description : Check reply_body_max_size value
-    if [ ${SQUID_DAEMON_RUNNING} -eq 1 -a ! -z "${SQUID_DAEMON_CONFIG}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ${SQUID_DAEMON_RUNNING} -eq 1 -a -n "${SQUID_DAEMON_CONFIG}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no SQD-3630 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check Squid reply_body_max_size option"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: checking option reply_body_max_size"
@@ -293,7 +293,7 @@
 #
 #################################################################################
 #
-    if [ ${SQUID_DAEMON_RUNNING} -eq 1 -a ! -z "${SQUID_DAEMON_CONFIG}" ]; then
+    if [ ${SQUID_DAEMON_RUNNING} -eq 1 -a -n "${SQUID_DAEMON_CONFIG}" ]; then
         Display --indent 4 --text "- Checking Squid general options"
     fi
 #
@@ -301,7 +301,7 @@
 #
     # Test        : SQD-3680
     # Description : Check httpd_suppress_version_string
-    if [ ${SQUID_DAEMON_RUNNING} -eq 1 -a ! -z "${SQUID_DAEMON_CONFIG}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ${SQUID_DAEMON_RUNNING} -eq 1 -a -n "${SQUID_DAEMON_CONFIG}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no SQD-3680 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check Squid version suppression"
     if [ ${SKIPTEST} -eq 0 ]; then
         FIND=$(${GREPBINARY} "^httpd_suppress_version_string " ${SQUID_DAEMON_CONFIG} | ${GREPBINARY} " on")
diff --git a/include/tests_ssh b/include/tests_ssh
index 8a55eabf..377d043f 100644
--- a/include/tests_ssh
+++ b/include/tests_ssh
@@ -104,7 +104,7 @@
     if [ ${SKIPTEST} -eq 0 ]; then
         OPENSSHD_VERSION=$(${SSHDBINARY} -t -d 2>&1 | ${GREPBINARY} 'sshd version' | ${AWKBINARY} '{if($4~OpenSSH_){print $4}}' | ${AWKBINARY} -F_ '{print $2}' | ${TRBINARY} -d '[:cntrl:],')
         LogText "Result: discovered OpenSSH version is ${OPENSSHD_VERSION}"
-        if [ ! -z ${OPENSSHD_VERSION} ]; then
+        if [ -n ${OPENSSHD_VERSION} ]; then
             OPENSSHD_VERSION_MAJOR=$(echo ${OPENSSHD_VERSION%%p*} | ${AWKBINARY} -F. '{print $1}')
             LogText "Result: OpenSSH major version: ${OPENSSHD_VERSION_MAJOR}"
             OPENSSHD_VERSION_MINOR=$(echo ${OPENSSHD_VERSION%%p*} | ${AWKBINARY} -F. '{print $2}')
@@ -117,7 +117,7 @@
     # Test        : SSH-7408
     # Description : Check SSH specific defined options
     # Notes       : Instead of parsing the configuration file, we query the SSH daemon itself
-    if [ ${OPENSSHD_RUNNING} -eq 1 -a ! -z "${SSH_DAEMON_OPTIONS_FILE}" -a ${OPENSSHD_VERSION_MAJOR} -ge 5 -a ${OPENSSHD_VERSION_MINOR} -ge 1 ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ${OPENSSHD_RUNNING} -eq 1 -a -n "${SSH_DAEMON_OPTIONS_FILE}" -a ${OPENSSHD_VERSION_MAJOR} -ge 5 -a ${OPENSSHD_VERSION_MINOR} -ge 1 ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no SSH-7408 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check SSH specific defined options"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking specific defined options in ${SSH_DAEMON_OPTIONS_FILE}"
@@ -189,7 +189,7 @@
                 FOUNDVALUE=$(${AWKBINARY} -v OPT="${OPTIONNAME_LOWER}" 'index($0, OPT) == 1 { print toupper($2) }' ${SSH_DAEMON_OPTIONS_FILE} | tail -1)
                 LogText "Test: Checking ${OPTIONNAME} in ${SSH_DAEMON_OPTIONS_FILE}"
 
-                if [ ! -z "${FOUNDVALUE}" ]; then
+                if [ -n "${FOUNDVALUE}" ]; then
                     LogText "Result: Option ${OPTIONNAME} found"
                     LogText "Result: Option ${OPTIONNAME} value is ${FOUNDVALUE}"
 
@@ -201,7 +201,7 @@
                         elif [ "${FOUNDVALUE}" = "${WEAKVALUE}" ]; then
                             RESULT="WEAK"
                         else
-                            if [ ! -z "${EXPECTEDVALUE}" ]; then
+                            if [ -n "${EXPECTEDVALUE}" ]; then
                                 LogText "Expected value has multiple values, testing if active value is in list (${EXPECTEDVALUE})"
                                 FIND=$(echo ${FOUNDVALUE} | ${GREPBINARY} -E "${EXPECTEDVALUE}")
                                 if [ $? -eq 0 ]; then
@@ -211,7 +211,7 @@
                                     LogText "Result: not found"
                                 fi
                             fi
-                            if [ ! -z "${MEDIUMSCOREDVALUE}" ]; then
+                            if [ -n "${MEDIUMSCOREDVALUE}" ]; then
                                 LogText "Medium scored value has multiple values, testing if active value is in list (${MEDIUMSCOREDVALUE})"
                                 FIND=$(echo ${FOUNDVALUE} | ${GREPBINARY} -E "${MEDIUMSCOREDVALUE}")
                                 if [ $? -eq 0 ]; then
@@ -296,13 +296,13 @@
     # Test        : SSH-7440
     # Description : OpenSSH - AllowUsers / AllowGroups
     # Goal        : Check if only a specific amount of users/groups can log in to the system
-    if [ ${OPENSSHD_RUNNING} -eq 1 -a ! -z "${SSH_DAEMON_OPTIONS_FILE}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ${OPENSSHD_RUNNING} -eq 1 -a -n "${SSH_DAEMON_OPTIONS_FILE}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no SSH-7440 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check OpenSSH option: AllowUsers and AllowGroups"
     if [ ${SKIPTEST} -eq 0 ]; then
         FOUND=0
         # AllowUsers
         FIND=$(${EGREPBINARY} -i "^AllowUsers" ${SSH_DAEMON_OPTIONS_FILE} | ${AWKBINARY} '{ print $2 }')
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             LogText "Result: AllowUsers set, with value ${FIND}"
             Display --indent 4 --text "- OpenSSH option: AllowUsers" --result "${STATUS_FOUND}" --color GREEN
             FOUND=1
@@ -313,7 +313,7 @@
 
         # AllowGroups
         FIND=$(${EGREPBINARY} -i "^AllowGroups" ${SSH_DAEMON_OPTIONS_FILE} | ${AWKBINARY} '{ print $2 }')
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             LogText "Result: AllowUsers set ${FIND}"
             Display --indent 4 --text "- OpenSSH option: AllowGroups" --result "${STATUS_FOUND}" --color GREEN
             FOUND=1
diff --git a/include/tests_storage b/include/tests_storage
index 34a92ec3..a9029852 100644
--- a/include/tests_storage
+++ b/include/tests_storage
@@ -37,10 +37,10 @@
         LogText "Test: Checking firewire storage driver in directory /etc/modprobe.d and configuration file /etc/modprobe.conf"
         if [ -d ${ROOTDIR}etc/modprobe.d ]; then
             FIND=$(${LSBINARY} ${ROOTDIR}etc/modprobe.d/* 2> /dev/null)
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 FIND1=$(${EGREPBINARY} "blacklist (ohci1394|firewire[-_]ohci|firewire-core)" ${ROOTDIR}etc/modprobe.d/* | ${GREPBINARY} -v "#")
                 FIND2=$(${EGREPBINARY} "install (ohci1394|firewire[-_]ohci|firewire-core) /bin/(false|true)" ${ROOTDIR}etc/modprobe.d/* | ${GREPBINARY} -v "#")
-                if [ ! -z "${FIND1}" -o ! -z "${FIND2}" ]; then
+                if [ -n "${FIND1}" -o -n "${FIND2}" ]; then
                     FOUND=1
                     LogText "Result: found firewire ohci driver in disabled state"
                 fi
@@ -51,7 +51,7 @@
         if [ -f ${ROOTDIR}etc/modprobe.conf ]; then
             FIND1=$(${EGREPBINARY} -r "blacklist (ohci1394|firewire[-_]ohci|firewire-core)" ${ROOTDIR}etc/modprobe.conf | ${GREPBINARY} -v "#")
             FIND2=$(${EGREPBINARY} -r "install (ohci1394|firewire[-_]ohci|firewire-core) /bin/(false|true)" ${ROOTDIR}etc/modprobe.conf | ${GREPBINARY} -v "#")
-            if [ ! -z "${FIND1}" -o ! -z "${FIND2}" ]; then
+            if [ -n "${FIND1}" -o -n "${FIND2}" ]; then
                 FOUND=1
                 LogText "Result: found firewire ohci driver in disabled state"
             fi
diff --git a/include/tests_storage_nfs b/include/tests_storage_nfs
index 4c0e39ef..bfc5192d 100644
--- a/include/tests_storage_nfs
+++ b/include/tests_storage_nfs
@@ -33,7 +33,7 @@
 #
     # Test        : STRG-1902
     # Description : Check rpcinfo
-    if [ ! -z "${RPCINFOBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${RPCINFOBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no STRG-1902 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check rpcinfo registered programs"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking rpcinfo registered programs"
@@ -48,7 +48,7 @@
 #
     # Test        : STRG-1904
     # Description : Check nfs versions in rpcinfo
-    if [ ! -z "${RPCINFOBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${RPCINFOBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no STRG-1904 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check nfs rpc"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking NFS registered versions"
@@ -63,7 +63,7 @@
 #
     # Test        : STRG-1906
     # Description : Check nfs protocols (TCP/UDP) and port in rpcinfo
-    if [ ! -z "${RPCINFOBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ -n "${RPCINFOBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no STRG-1906 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check nfs rpc"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking NFS registered protocols"
@@ -123,7 +123,7 @@
         if [ -f ${ROOTDIR}etc/exports ]; then
             LogText "Result: ${ROOTDIR}etc/exports exists"
             FIND=$(${GREPBINARY} -v "^$" ${ROOTDIR}etc/exports | ${GREPBINARY} -v "^#" | ${SEDBINARY} 's/ /!space!/g')
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 for I in ${FIND}; do
                     I=$(echo ${I} | ${SEDBINARY} 's/!space!/ /g')
                     LogText "Found line: ${I}"
@@ -161,7 +161,7 @@
     Register --test-no STRG-1930 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check client access to nfs share"
     if [ ${SKIPTEST} -eq 0 ]; then
         sFIND=$(${SHOWMOUNTBINARY} -e | ${AWKBINARY} '{ print $2 }' | ${SEDBINARY} '1d' | ${GREPBINARY} "\*")
-        if [ ! -z "${sFIND}" ]; then
+        if [ -n "${sFIND}" ]; then
             LogText "Result: all client are allowed to access a NFS share in /etc/exports"
             Display --indent 4 --text "- Checking NFS client access" --result "ALL CLIENTS" --color YELLOW
             ReportSuggestion ${TEST_NO} "Specify clients that are allowed to access a NFS share /etc/exports"
diff --git a/include/tests_time b/include/tests_time
index d67580b8..27693236 100644
--- a/include/tests_time
+++ b/include/tests_time
@@ -62,7 +62,7 @@
         for FILE in ${SEARCH_FILES}; do
             if [ -f ${FILE} ]; then LogText "result: found chrony configuration: ${FILE}"; CHRONY_CONF_FILE="${FILE}"; fi
         done
-        if [ ! -z "${CHRONY_CONF_FILE}" ]; then
+        if [ -n "${CHRONY_CONF_FILE}" ]; then
             IsRunning chronyd
             if [ ${RUNNING} -eq 1 ]; then
                 FOUND=1; NTP_DAEMON_RUNNING=1; NTP_CONFIG_TYPE_DAEMON=1; NTP_DAEMON="chronyd"
@@ -83,7 +83,7 @@
 
         # Check running processes
         FIND=$(${PSBINARY} ax | ${GREPBINARY} "ntpd" | ${GREPBINARY} -v "dntpd" | ${GREPBINARY} -v "grep")
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             FOUND=1; NTPD_RUNNING=1; NTP_DAEMON_RUNNING=1; NTP_CONFIG_TYPE_DAEMON=1
             NTP_DAEMON="ntpd"
             LogText "Result: found running NTP daemon in process list"
@@ -98,9 +98,9 @@
         fi
 
         # Check timedate daemon (systemd)
-        if [ ! -z "${TIMEDATECTL}" ]; then
+        if [ -n "${TIMEDATECTL}" ]; then
             FIND=$(${TIMEDATECTL} status | ${EGREPBINARY} "(NTP|System clock) synchronized: yes")
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 # Check for systemd-timesyncd
                 if [ -f ${ROOTDIR}etc/systemd/timesyncd.conf ]; then
                     LogText "Result: found ${ROOTDIR}etc/systemd/timesyncd.conf"
@@ -124,7 +124,7 @@
             if [ -f ${I} ]; then
                 LogText "Test: checking for ntpdate or rdate in crontab file ${I}"
                 FIND=$(${EGREPBINARY} "ntpdate|rdate" ${I} | ${GREPBINARY} -v '^#')
-                if [ ! -z "${FIND}" ]; then
+                if [ -n "${FIND}" ]; then
                     FOUND=1; NTP_CONFIG_TYPE_SCHEDULED=1
                     Display --indent 2 --text "- Checking NTP client in crontab file (${I})" --result "${STATUS_FOUND}" --color GREEN
                     LogText "Result: found ntpdate or rdate reference in crontab file ${I}"
@@ -146,11 +146,11 @@
             if [ -d ${I} ]; then
                 if FileIsReadable ${I}; then
                     FIND=$(${LSBINARY} ${I} | ${GREPBINARY} -v FIFO)
-                    if [ ! -z "${FIND}" ]; then
+                    if [ -n "${FIND}" ]; then
                         for J in ${FIND}; do
                             LogText "Test: checking for ntpdate or rdate in ${I}/${J}"
                             FIND2=$(${EGREPBINARY} "rdate|ntpdate" ${I}/${J} | ${GREPBINARY} -v "^#")
-                            if [ ! -z "${FIND2}" ]; then
+                            if [ -n "${FIND2}" ]; then
                                 LogText "Positive match found: ${FIND2}"
                                 FOUND=1; FOUND_IN_CRON=1; NTP_CONFIG_TYPE_SCHEDULED=1
                             fi
@@ -186,7 +186,7 @@
         if [ -f /etc/rc.conf ]; then
             LogText "Test: Checking if ntpdate is enabled at startup in *BSD"
             FIND=$(${GREPBINARY} 'ntpdate_enable="YES"' /etc/rc.conf)
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 LogText "Result: ntpdate is enabled in rc.conf"
                 FOUND=1
                 NTP_CONFIG_TYPE_STARTUP=1
@@ -219,7 +219,7 @@
 #
     # Test        : TIME-3106
     # Description : Check status of systemd time synchronization
-    if [ ${SYSTEMD_NTP_ENABLED} -eq 1 -a ! -z "${TIMEDATECTL}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ${SYSTEMD_NTP_ENABLED} -eq 1 -a -n "${TIMEDATECTL}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no TIME-3106 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check systemd NTP time synchronization status"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Check the status of time synchronization via timedatectl"
@@ -234,7 +234,7 @@
 #
     # Test        : TIME-3112
     # Description : Check for valid associations from ntpq peers list
-    if [ ${NTPD_RUNNING} -eq 1 -a ! -z "${NTPQBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ${NTPD_RUNNING} -eq 1 -a -n "${NTPQBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no TIME-3112 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check active NTP associations ID's"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking for NTP association ID's from ntpq peers list"
@@ -252,7 +252,7 @@
 #
     # Test        : TIME-3116
     # Description : Check for stratum 16 peers
-    if [ ${NTPD_RUNNING} -eq 1 -a ! -z "${NTPQBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ${NTPD_RUNNING} -eq 1 -a -n "${NTPQBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no TIME-3116 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check peers with stratum value of 16"
     if [ ${SKIPTEST} -eq 0 ]; then
         COUNT=0
@@ -290,7 +290,7 @@
     # Description : Check unreliable peers from peer list
     # Notes       : Items with # are too far away (network distance)
     #               Items with - are not chosen due clustering algorithm
-    if [ ${NTPD_RUNNING} -eq 1 -a ! -z "${NTPQBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ${NTPD_RUNNING} -eq 1 -a -n "${NTPQBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no TIME-3120 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check unreliable NTP peers"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking unreliable ntp peers"
@@ -313,13 +313,13 @@
 #
     # Test        : TIME-3124
     # Description : Check selected time source
-    if [ ${NTPD_RUNNING} -eq 1 -a ! -z "${NTPQBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ${NTPD_RUNNING} -eq 1 -a -n "${NTPQBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no TIME-3124 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check selected time source"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking selected time source"
         FIND=$(${NTPQBINARY} -p -n | ${GREPBINARY} '^*' | ${AWKBINARY} '{ if ($4=="l") { print $1 } }')
         FIND2=$(${NTPQBINARY} -p -n | ${GREPBINARY} '^*' | ${AWKBINARY} '{ print $1 }')
-        if [ -z "${FIND}" -a ! -z "${FIND2}" ]; then
+        if [ -z "${FIND}" -a -n "${FIND2}" ]; then
             Display --indent 2 --text "- Checking selected time source" --result "${STATUS_OK}" --color GREEN
             FIND2=$(echo ${FIND2} | ${SEDBINARY} 's/*//g')
             LogText "Result: Found selected time source (value: ${FIND2})"
@@ -335,7 +335,7 @@
 #
     # Test        : TIME-3128
     # Description : Check time source candidates
-    if [ ${NTPD_RUNNING} -eq 1 -a ! -z "${NTPQBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ${NTPD_RUNNING} -eq 1 -a -n "${NTPQBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no TIME-3128 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check preferred time source"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking preferred time source"
@@ -358,7 +358,7 @@
 #
     # Test        : TIME-3132
     # Description : Check ntpq falsetickers
-    if [ ${NTPD_RUNNING} -eq 1 -a ! -z "${NTPQBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ${NTPD_RUNNING} -eq 1 -a -n "${NTPQBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no TIME-3132 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check NTP falsetickers"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking preferred time source"
@@ -382,7 +382,7 @@
 #
     # Test        : TIME-3136
     # Description : Check ntpq reported ntp version (Linux)
-    if [ ${NTPD_RUNNING} -eq 1 -a ! -z "${NTPQBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ${NTPD_RUNNING} -eq 1 -a -n "${NTPQBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no TIME-3136 --os Linux --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check NTP protocol version"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: Checking NTP protocol version (ntpq -c ntpversion)"
@@ -403,7 +403,7 @@
     # Test        : TIME-3146
     # Description : Check /etc/default/ntpdate (Linux)
     # Notes       : ntpdate-debian binary
-    #if [ ${NTPD_RUNNING} -eq 1 -a ! -z "${NTPQBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    #if [ ${NTPD_RUNNING} -eq 1 -a -n "${NTPQBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     #Register --test-no TIME-3146 --os Linux --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check /etc/default/ntpdate"
     #if [ ${SKIPTEST} -eq 0 ]; then
 #
@@ -428,7 +428,7 @@
     # Description : Check empty NTP step-tickers
     # Notes       : Mostly applies to Red Hat and clones
     FILE="${ROOTDIR}etc/ntp/step-tickers"
-    if [ "${NTPD_RUNNING}" -eq 1 -a ! -z "${NTPQBINARY}" -a -f "${FILE}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ "${NTPD_RUNNING}" -eq 1 -a -n "${NTPQBINARY}" -a -f "${FILE}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no TIME-3160 --os Linux --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check empty NTP step-tickers"
     if [ ${SKIPTEST} -eq 0 ]; then
         FOUND=0
diff --git a/include/tests_tooling b/include/tests_tooling
index c752dbde..f07bcdac 100644
--- a/include/tests_tooling
+++ b/include/tests_tooling
@@ -71,7 +71,7 @@
         fi
 
         # Cfengine
-        if [ ! -z "${CFAGENTBINARY}" ]; then
+        if [ -n "${CFAGENTBINARY}" ]; then
             LogText "Result: CFEngine (cfagent) is installed (${CFAGENTBINARY})"
             AUTOMATION_TOOL_FOUND=1
             CFENGINE_AGENT_FOUND=1
@@ -129,7 +129,7 @@
             fi
         fi
 
-        if [ ! -z "${PUPPETBINARY}" ]; then
+        if [ -n "${PUPPETBINARY}" ]; then
             LogText "Result: Puppet is installed (${PUPPETBINARY})"
             AUTOMATION_TOOL_FOUND=1
             Report "automation_tool_running[]=puppet-agent"
@@ -145,14 +145,14 @@
         fi
 
         # SaltStack
-        if [ ! -z "${SALTMINIONBINARY}" ]; then
+        if [ -n "${SALTMINIONBINARY}" ]; then
             LogText "Result: SaltStack (salt-minion) is installed (${SALTMINIONBINARY})"
             AUTOMATION_TOOL_FOUND=1
             SALT_MINION_RUNNING=1
             Report "automation_tool_running[]=saltstack-minion"
             Display --indent 4 --text "- SaltStack minion (salt-minion)" --result "${STATUS_FOUND}" --color GREEN
         fi
-        if [ ! -z "${SALTMASTERBINARY}" ]; then
+        if [ -n "${SALTMASTERBINARY}" ]; then
             LogText "Result: SaltStack (salt-master) is installed (${SALTMASTERBINARY})"
             AUTOMATION_TOOL_FOUND=1
             SALT_MASTER_RUNNING=1
@@ -188,7 +188,7 @@
     if [ ${SKIPTEST} -eq 0 ]; then
 
         # Fail2ban presence
-        if [ ! -z "${FAIL2BANBINARY}" ]; then
+        if [ -n "${FAIL2BANBINARY}" ]; then
             FAIL2BAN_FOUND=1
             IDS_IPS_TOOL_FOUND=1
             LogText "Result: Fail2ban is installed (${FAIL2BANBINARY})"
@@ -209,10 +209,10 @@
         fi
 
         # Continue if tooling is available and configuration file found
-        if [ ${FAIL2BAN_FOUND} -eq 1 -a ! -z "${FAIL2BAN_CONFIG}" ]; then
+        if [ ${FAIL2BAN_FOUND} -eq 1 -a -n "${FAIL2BAN_CONFIG}" ]; then
             Report "fail2ban_config=${FAIL2BAN_CONFIG}"
             FAIL2BANCLIENT=$(which fail2ban-client 2> /dev/null | grep -v "no [^ ]* in ")
-            if [ ! -z "${FAIL2BANCLIENT}" ]; then PERFORM_FAIL2BAN_TESTS=1; fi
+            if [ -n "${FAIL2BANCLIENT}" ]; then PERFORM_FAIL2BAN_TESTS=1; fi
         fi
     fi
 #
@@ -224,7 +224,7 @@
     Register --test-no TOOL-5104 --weight L --network NO --preqs-met ${PREQS_MET} --category security --description "Enabled tests in Fail2ban"
     if [ ${SKIPTEST} -eq 0 ]; then
         FIND=$(${FAIL2BANCLIENT} -d | ${TRBINARY} -d '[]' | ${TRBINARY} -d "'" | ${AWKBINARY} -F, '{ if ($1=="add") { print $2 }}' | ${TRBINARY} -d ' ')
-        if [ ! -z "${FIND}" ]; then
+        if [ -n "${FIND}" ]; then
             for F2BSERVICE in ${FIND}; do
                 LogText "Result: service '${F2BSERVICE}' enabled"
                 Report "fail2ban_enabled_service[]=${F2BSERVICE}"
@@ -252,12 +252,12 @@
     #            FIND=$(${EGREPBINARY} "^action = \%\(action_m.*\)s" ${FAIL2BAN_CONFIG})
     #            FIND2=$(${EGREPBINARY} "^action = \%\(action_\)s" ${FAIL2BAN_CONFIG})
     #
-    #            if [ ! -z "${FIND}" ]; then
+    #            if [ -n "${FIND}" ]; then
     #                FAIL2BAN_EMAIL=1
     #                LogText "Result: found at least one jail which sends an email alert"
     #            fi
     #
-    #            if [ ! -z "${FIND2}" ]; then
+    #            if [ -n "${FIND2}" ]; then
     #                FAIL2BAN_SILENT=1
     #                LogText "Result: found at least one jail which does NOT send an email alert"
     #            fi
@@ -298,9 +298,9 @@
     #
     #            LogText "Checking for fail2ban iptables chains"
     #
-    #            if [ ! -z "${IPTABLESBINARY}" ]; then
+    #            if [ -n "${IPTABLESBINARY}" ]; then
     #                CHECK_CHAINS=$(${IPTABLESBINARY} -L 2>&1 | ${GREPBINARY} fail2ban)
-    #                if [ ! -z "${CHECK_CHAINS}" ]; then
+    #                if [ -n "${CHECK_CHAINS}" ]; then
     #                    LogText "Result: found at least one iptables chain for fail2ban"
     #                    Display --indent 4 --text "- Checking for Fail2ban iptables chain" --result "${STATUS_OK}" --color GREEN
     #                else
diff --git a/include/tests_usb b/include/tests_usb
index eada5d12..3ba19cc9 100644
--- a/include/tests_usb
+++ b/include/tests_usb
@@ -39,7 +39,7 @@
 #
     # Test to determine if USBGuard is installed.  If it is, we will limit
     # suggestions from other tests.
-    if [ ! -z "${USBGUARDBINARY}" ]; then
+    if [ -n "${USBGUARDBINARY}" ]; then
         USBGUARD_FOUND=1
     fi
 #
@@ -53,10 +53,10 @@
         LogText "Test: Checking USB storage driver in directory /etc/modprobe.d and configuration file /etc/modprobe.conf"
         if [ -d /etc/modprobe.d ]; then
             FIND=$(${LSBINARY} ${ROOTDIR}etc/modprobe.d/* 2> /dev/null)
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 FIND=$(${EGREPBINARY} -r "install usb[-_]storage /bin/(false|true)" ${ROOTDIR}etc/modprobe.d/* | ${GREPBINARY} -v "#")
                 FIND2=$(${EGREPBINARY} -r "^blacklist usb[-_]storage" ${ROOTDIR}etc/modprobe.d/*)
-                if [ ! -z "${FIND}" -o ! -z "${FIND2}" ]; then
+                if [ -n "${FIND}" -o -n "${FIND2}" ]; then
                     FOUND=1
                     LogText "Result: found usb-storage driver in disabled state (blacklisted)"
                 fi
@@ -66,7 +66,7 @@
         fi
         if [ -f ${ROOTDIR}etc/modprobe.conf ]; then
             FIND=$(${EGREPBINARY} "install usb[-_]storage /bin/(false|true)" ${ROOTDIR}etc/modprobe.conf | ${GREPBINARY} "usb-storage" | ${GREPBINARY} -v "#")
-            if [ ! -z "${FIND}" ]; then
+            if [ -n "${FIND}" ]; then
                 FOUND=1
                 LogText "Result: found usb-storage driver in disabled state"
             fi
@@ -146,14 +146,14 @@
                 USBGUARD_CONFIG=""
             fi
 
-            if [ ! -z "${USBGUARD_CONFIG}" ]; then
+            if [ -n "${USBGUARD_CONFIG}" ]; then
                 LogText "Result: USBGuard configuration found (${USBGUARD_CONFIG})"
                 Display --indent 4 --text "- Configuration" --result "${STATUS_FOUND}" --color GREEN
                 AddHP 1 1
 
                 LogText "Checking USBGuard restore controller device state (RestoreControllerDeviceState)"
                 USBGUARD_RESTORE_POLICY=$(${AWKBINARY} -F '=' -v OPT="RestoreControllerDeviceState" 'index($0, OPT) == 1 {print $2}' ${USBGUARD_CONFIG})
-                if [ ! -z "${USBGUARD_RESTORE_POLICY}" ]; then
+                if [ -n "${USBGUARD_RESTORE_POLICY}" ]; then
                     LogText "Result: RestoreControllerDeviceState = ${USBGUARD_RESTORE_POLICY}"
                     case "${USBGUARD_RESTORE_POLICY}" in
                         "true")
@@ -184,7 +184,7 @@
 
                 LogText "Checking USBGuard rule for controllers connected before daemon starts (PresentControllerPolicy)"
                 USBGUARD_CONTROLLER_POLICY=$(${AWKBINARY} -F '=' -v OPT="PresentControllerPolicy" 'index($0, OPT) == 1 {print $2}' ${USBGUARD_CONFIG})
-                if [ ! -z "${USBGUARD_CONTROLLER_POLICY}" ]; then
+                if [ -n "${USBGUARD_CONTROLLER_POLICY}" ]; then
                     LogText "Result: PresentControllerPolicy = ${USBGUARD_CONTROLLER_POLICY}"
                     case "${USBGUARD_CONTROLLER_POLICY}" in
                         "allow" | "keep")
@@ -214,7 +214,7 @@
 
                 LogText "Checking USBGuard rule for devices connected before daemon starts (PresentDevicePolicy)"
                 USBGUARD_DEVICE_POLICY=$(${AWKBINARY} -F '=' -v OPT="PresentDevicePolicy" 'index($0, OPT) == 1 {print $2}' ${USBGUARD_CONFIG})
-                if [ ! -z "${USBGUARD_DEVICE_POLICY}" ]; then
+                if [ -n "${USBGUARD_DEVICE_POLICY}" ]; then
                     LogText "Result: PresentDevicePolicy = ${USBGUARD_DEVICE_POLICY}"
                     case "${USBGUARD_DEVICE_POLICY}" in
                         "allow" | "keep")
@@ -244,7 +244,7 @@
 
                 LogText "Checking USBGuard rule for devices inserted after daemon starts (InsertedDevicePolicy)"
                 USBGUARD_INSERTED_POLICY=$(${AWKBINARY} -F '=' -v OPT="InsertedDevicePolicy" 'index($0, OPT) == 1 {print $2}' ${USBGUARD_CONFIG})
-                if [ ! -z "${USBGUARD_INSERTED_POLICY}" ]; then
+                if [ -n "${USBGUARD_INSERTED_POLICY}" ]; then
                     LogText "Result: InsertedDevicePolicy = ${USBGUARD_INSERTED_POLICY}"
                     case "${USBGUARD_INSERTED_POLICY}" in
                         "allow" | "keep")
@@ -274,7 +274,7 @@
 
                 LogText "Checking USBGuard rule for devices not in RuleFile (ImplicitPolicyTarget)"
                 USBGUARD_DEFAULT_POLICY=$(${AWKBINARY} -F '=' -v OPT="ImplicitPolicyTarget" 'index($0, OPT) == 1 {print $2}' ${USBGUARD_CONFIG})
-                if [ ! -z "${USBGUARD_DEFAULT_POLICY}" ]; then
+                if [ -n "${USBGUARD_DEFAULT_POLICY}" ]; then
                     LogText "Result: ImplicitPolicyTarget = ${USBGUARD_DEFAULT_POLICY}"
                     case "${USBGUARD_DEFAULT_POLICY}" in
                         "allow")
@@ -304,7 +304,7 @@
 
                 LogText "Checking RuleFile"
                 USBGUARD_RULES=$(${AWKBINARY} -F '=' -v OPT="RuleFile" 'index($0, OPT) == 1 {print $2}' ${USBGUARD_CONFIG})
-                if [ ! -z "${USBGUARD_RULES}" ] && [ -f "${USBGUARD_RULES}" ]; then
+                if [ -n "${USBGUARD_RULES}" ] && [ -f "${USBGUARD_RULES}" ]; then
                     LogText "Result: RuleFile found (${USBGUARD_RULES})"
                     Display --indent 4 --text "- RuleFile" --result "${STATUS_FOUND}" --color GREEN
                     AddHP 1 1
diff --git a/include/tests_webservers b/include/tests_webservers
index dfe8aabc..be78fb11 100644
--- a/include/tests_webservers
+++ b/include/tests_webservers
@@ -157,7 +157,7 @@
                 done
                 # Search Server aliases
                 for J in $(${GREPBINARY} "ServerAlias" ${I} | ${GREPBINARY} -v "^#" | ${SEDBINARY} "s/\s*ServerAlias //g" | ${SEDBINARY} "s/#.*//g"); do
-                    if [ ! -z ${J} ]; then
+                    if [ -n ${J} ]; then
                         tVHOSTS="${tVHOSTS} ${J}"
                         cVHOSTS=$((cVHOSTS + 1))
                     fi
@@ -170,7 +170,7 @@
 
         # Log all virtual hosts we found
             for J in ${tVHOSTS}; do
-                if [ ! -z ${J} ]; then
+                if [ -n ${J} ]; then
                     LogText "Virtual host: ${J}"
                     #Report "apache_vhost_name[]=${J}"
                 fi
@@ -186,10 +186,10 @@
     fi
 
     # Remove temp files
-    if [ -f ${TMPFILE} -a ! -z "${TMPFILE}" ]; then
+    if [ -f ${TMPFILE} -a -n "${TMPFILE}" ]; then
         rm -f ${TMPFILE}
     fi
-    if [ ! -z "${TMPFILE2}" ]; then if [ -f ${TMPFILE2} ]; then rm -f ${TMPFILE2}; fi; fi
+    if [ -n "${TMPFILE2}" ]; then if [ -f ${TMPFILE2} ]; then rm -f ${TMPFILE2}; fi; fi
 #
 #################################################################################
 #
@@ -351,7 +351,7 @@
     # Test        : HTTP-6706
     # Description : Search for includes within nginx configuration file
     # Notes       : Daemon nginx should be running, nginx.conf should be found
-    if [ ${NGINX_RUNNING} -eq 1 -a ! -z "${NGINX_CONF_LOCATION}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ${NGINX_RUNNING} -eq 1 -a -n "${NGINX_CONF_LOCATION}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no HTTP-6706 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check for additional nginx configuration files"
     if [ ${SKIPTEST} -eq 0 ]; then
         CreateTempFile || ExitFatal
@@ -402,7 +402,7 @@
     # Test        : HTTP-6708
     # Description : Check discovered nginx configuration settings for further hardening
     # Notes       : Daemon of nginx should be running, nginx.conf should be found
-    if [ ${NGINX_RUNNING} -eq 1 -a ! -z "${NGINX_CONF_FILES}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ${NGINX_RUNNING} -eq 1 -a -n "${NGINX_CONF_FILES}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no HTTP-6708 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check discovered nginx configuration settings"
     if [ ${SKIPTEST} -eq 0 ]; then
         LogText "Test: start parsing all discovered nginx options"
@@ -420,7 +420,7 @@
                 LogText "Result: this configuration file is skipped, as it contains usually no interesting details"
             fi
         done
-        if [ ! -z "${NGINX_CONF_FILES_ADDITIONS}" ]; then
+        if [ -n "${NGINX_CONF_FILES_ADDITIONS}" ]; then
             for I in ${NGINX_CONF_FILES_ADDITIONS}; do
                 FILENAME=$(echo ${I} | ${AWKBINARY} -F/ '{print $NF}')
                 if [ ! "${FILENAME}" = "mime.types" ]; then
@@ -442,7 +442,7 @@
     # Test        : HTTP-6710
     # Description : Check SSL configuration of nginx
     # Notes       : Daemon of nginx should be running, nginx.conf should be found
-    if [ ${NGINX_RUNNING} -eq 1 -a ! -z "${NGINX_CONF_LOCATION}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ${NGINX_RUNNING} -eq 1 -a -n "${NGINX_CONF_LOCATION}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no HTTP-6710 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check nginx SSL configuration settings"
     if [ ${SKIPTEST} -eq 0 ]; then
         NGINX_SSL_SUGGESTION=0
@@ -494,7 +494,7 @@
     # Test        : HTTP-6712
     # Description : Check logging configuration of nginx
     # Notes       : Daemon of nginx should be running, nginx.conf should be found
-    if [ ${NGINX_RUNNING} -eq 1 -a ! -z "${NGINX_CONF_LOCATION}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ${NGINX_RUNNING} -eq 1 -a -n "${NGINX_CONF_LOCATION}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no HTTP-6712 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check nginx access logging"
     if [ ${SKIPTEST} -eq 0 ]; then
         NGINX_LOG_SUGGESTION=0
@@ -528,7 +528,7 @@
 #
     # Test        : HTTP-6714
     # Description : Check missing error logs in nginx
-    if [ ${NGINX_RUNNING} -eq 1 -a ! -z "${NGINX_CONF_LOCATION}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ${NGINX_RUNNING} -eq 1 -a -n "${NGINX_CONF_LOCATION}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no HTTP-6714 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check for missing error logs in nginx"
     if [ ${SKIPTEST} -eq 0 ]; then
         NGINX_LOG_SUGGESTION=0
@@ -549,7 +549,7 @@
 #
     # Test        : HTTP-6716
     # Description : Check debug mode on error log in nginx
-    if [ ${NGINX_RUNNING} -eq 1 -a ! -z "${NGINX_CONF_LOCATION}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
+    if [ ${NGINX_RUNNING} -eq 1 -a -n "${NGINX_CONF_LOCATION}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
     Register --test-no HTTP-6716 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check for debug mode on error log in nginx"
     if [ ${SKIPTEST} -eq 0 ]; then
         NGINX_LOG_SUGGESTION=0
@@ -606,8 +606,8 @@
 #################################################################################
 #
     # Remove temp file (double check)
-    if [ ! -z "${TMPFILE}" ]; then if [ -f ${TMPFILE} ]; then rm -f ${TMPFILE}; fi; fi
-    if [ ! -z "${TMPFILE2}" ]; then if [ -f ${TMPFILE2} ]; then rm -f ${TMPFILE2}; fi; fi
+    if [ -n "${TMPFILE}" ]; then if [ -f ${TMPFILE} ]; then rm -f ${TMPFILE}; fi; fi
+    if [ -n "${TMPFILE2}" ]; then if [ -f ${TMPFILE2} ]; then rm -f ${TMPFILE2}; fi; fi
 
     WaitForKeyPress
 
diff --git a/include/tool_tips b/include/tool_tips
index bf529ca2..4f2f3b6e 100644
--- a/include/tool_tips
+++ b/include/tool_tips
@@ -48,7 +48,7 @@
         # Bash completion support
         #
         # Detect if bash is used for active user
-        #if [ ! -z "${ETC_PATHS}" ]; then
+        #if [ -n "${ETC_PATHS}" ]; then
         #    for I in ${ETC_PATHS}; do
         #        if [ -d ${I}/bash_completion.d ]; then
         #            if [ ! -f ${ETC_PATHS}/bash_completion.d/lynis ]; then
diff --git a/lynis b/lynis
index 8476efe0..35a023ef 100755
--- a/lynis
+++ b/lynis
@@ -538,8 +538,8 @@ ${NORMAL}
     Report "os_fullname=${OS_FULLNAME}"
     Report "os_version=${OS_VERSION}"
     if [ "${OS}" = "Linux" ]; then Report "linux_version=${LINUX_VERSION}"; fi
-    if [ ! -z "${OS_KERNELVERSION}" ]; then Report "os_kernel_version=${OS_KERNELVERSION}"; fi
-    if [ ! -z "${OS_KERNELVERSION_FULL}" ]; then Report "os_kernel_version_full=${OS_KERNELVERSION_FULL}"; fi
+    if [ -n "${OS_KERNELVERSION}" ]; then Report "os_kernel_version=${OS_KERNELVERSION}"; fi
+    if [ -n "${OS_KERNELVERSION_FULL}" ]; then Report "os_kernel_version_full=${OS_KERNELVERSION_FULL}"; fi
 
     Report "hostname=${HOSTNAME}"
 
@@ -635,7 +635,7 @@ ${NORMAL}
             LogText "Note: the end-of-life of '${OS_FULLNAME}' could not be checked. Entry missing in software-eol.db?"
         fi
 
-        if [ ! -z "${OS_MODE}" ]; then echo "  Operating system mode:     ${OS_MODE}"; fi
+        if [ -n "${OS_MODE}" ]; then echo "  Operating system mode:     ${OS_MODE}"; fi
         echo "  Kernel version:            ${OS_KERNELVERSION}"
         echo "  Hardware platform:         ${HARDWARE}"
         echo "  Hostname:                  ${HOSTNAME}"
@@ -658,9 +658,9 @@ ${NORMAL}
     LogText "Operating system:          ${OS}"
     LogText "Operating system name:     ${OS_NAME}"
     LogText "Operating system version:  ${OS_VERSION}"
-    if [ ! -z "${OS_MODE}" ]; then LogText "Operating system mode:     ${OS_MODE}"; fi
+    if [ -n "${OS_MODE}" ]; then LogText "Operating system mode:     ${OS_MODE}"; fi
     LogText "Kernel version:            ${OS_KERNELVERSION}"
-    if [ ! -z "${OS_KERNELVERSION_FULL}" ]; then
+    if [ -n "${OS_KERNELVERSION_FULL}" ]; then
         LogText "Kernel version (full):     ${OS_KERNELVERSION_FULL}"
     fi
     LogText "Hardware platform:         ${HARDWARE}"
@@ -872,7 +872,7 @@ ${NORMAL}
                         for PROFILE in ${PROFILES}; do
                             LogText "Action: checking plugin status in profile: ${PROFILE}"
                             FIND3=$(grep "^plugin=${FIND2}" ${PROFILE})
-                            if [ ! -z "${FIND3}" ]; then
+                            if [ -n "${FIND3}" ]; then
                                 FOUND=0
                                 for I in ${DISABLED_PLUGINS}; do
                                     if [ "${I}" = "${FIND2}" ]; then