diff --git a/client/powerline.sh b/client/powerline.sh
index 8bcec224..ad278c28 100755
--- a/client/powerline.sh
+++ b/client/powerline.sh
@@ -10,7 +10,7 @@ if test -n "$OSTYPE" ; then
 	elif test "${OSTYPE#darwin}" ; then
 		darwin=1
 	fi
-elif which uname >/dev/null ; then
+elif command -v uname >/dev/null ; then
 	if uname -o | grep -iqF linux ; then
 		use_filesystem=
 	elif uname -o | grep -iqF darwin ; then
diff --git a/powerline/bindings/bash/powerline.sh b/powerline/bindings/bash/powerline.sh
index f4e933ec..2c0943c3 100644
--- a/powerline/bindings/bash/powerline.sh
+++ b/powerline/bindings/bash/powerline.sh
@@ -1,5 +1,5 @@
 _powerline_columns_fallback() {
-	if which stty &>/dev/null ; then
+	if command -v stty &>/dev/null ; then
 		local cols="$(stty size 2>/dev/null)"
 		if ! test -z "$cols" ; then
 			echo "${cols#* }"
@@ -138,7 +138,7 @@ _powerline_setup_prompt() {
 }
 
 if test -z "${POWERLINE_CONFIG_COMMAND}" ; then
-	if which powerline-config >/dev/null ; then
+	if command -v powerline-config >/dev/null ; then
 		POWERLINE_CONFIG_COMMAND=powerline-config
 	else
 		POWERLINE_CONFIG_COMMAND="$(dirname "$BASH_SOURCE")/../../../scripts/powerline-config"
diff --git a/powerline/bindings/shell/powerline.sh b/powerline/bindings/shell/powerline.sh
index 15e13f26..e1b067dc 100644
--- a/powerline/bindings/shell/powerline.sh
+++ b/powerline/bindings/shell/powerline.sh
@@ -1,6 +1,6 @@
 _POWERLINE_SOURCED="$_"
 _powerline_columns_fallback() {
-	if which stty >/dev/null ; then
+	if command -v stty >/dev/null ; then
 		# Ksh does not have “local” built-in
 		_powerline_cols="$(stty size 2>/dev/null)"
 		if ! test -z "$_powerline_cols" ; then
@@ -220,7 +220,7 @@ _powerline_init_tmux_support() {
 }
 
 if test -z "${POWERLINE_CONFIG_COMMAND}" ; then
-	if which powerline-config >/dev/null ; then
+	if command -v powerline-config >/dev/null ; then
 		POWERLINE_CONFIG_COMMAND=powerline-config
 	else
 		POWERLINE_CONFIG_COMMAND="$(dirname "$_POWERLINE_SOURCED")/../../../scripts/powerline-config"
diff --git a/tests/shlib/common.sh b/tests/shlib/common.sh
index 63302625..77941922 100644
--- a/tests/shlib/common.sh
+++ b/tests/shlib/common.sh
@@ -143,7 +143,7 @@ rm_test_root() {
 	fi
 }
 
-if ! which realpath ; then
+if ! command -v realpath ; then
 	realpath() {
 		$PYTHON -c 'import os, sys; print(os.path.realpath(sys.argv[1]))' "$1"
 	}
diff --git a/tests/shlib/vterm.sh b/tests/shlib/vterm.sh
index 56b6c89b..bf95bb11 100644
--- a/tests/shlib/vterm.sh
+++ b/tests/shlib/vterm.sh
@@ -6,8 +6,8 @@ vterm_setup() {
 
 	mkdir "$TEST_ROOT/path"
 
-	ln -s "$(which "${PYTHON}")" "$TEST_ROOT/path/python"
-	ln -s "$(which bash)" "$TEST_ROOT/path"
+	ln -s "$(command -v "${PYTHON}")" "$TEST_ROOT/path/python"
+	ln -s "$(command -v bash)" "$TEST_ROOT/path"
 
 	cp -r "$ROOT/tests/terminfo" "$TEST_ROOT"
 }
diff --git a/tests/test_awesome/test.sh b/tests/test_awesome/test.sh
index fc85dc21..7a5614ec 100755
--- a/tests/test_awesome/test.sh
+++ b/tests/test_awesome/test.sh
@@ -13,20 +13,20 @@ cp -r "$TEST_STATIC_ROOT/powerline" "$TEST_ROOT"
 
 export PYTHONPATH="$ROOT${PYTHONPATH:+:}$PYTHONPATH"
 
-ln -s "$(which "${PYTHON}")" "$TEST_PATH"/python
-ln -s "$(which cat)" "$TEST_PATH"
-ln -s "$(which sh)" "$TEST_PATH"
-ln -s "$(which env)" "$TEST_PATH"
-if which socat ; then
-	ln -s "$(which socat)" "$TEST_PATH"
+ln -s "$(command -v "${PYTHON}")" "$TEST_PATH"/python
+ln -s "$(command -v cat)" "$TEST_PATH"
+ln -s "$(command -v sh)" "$TEST_PATH"
+ln -s "$(command -v env)" "$TEST_PATH"
+if command -v socat ; then
+	ln -s "$(command -v socat)" "$TEST_PATH"
 fi
 for pexe in powerline powerline.sh powerline.py ; do
 	if test -e scripts/$pexe ; then
 		ln -s "$PWD/scripts/$pexe" $TEST_ROOT/path
 	elif test -e client/$pexe ; then
 		ln -s "$PWD/client/$pexe" $TEST_ROOT/path
-	elif which $pexe ; then
-		ln -s "$(which $pexe)" $TEST_ROOT/path
+	elif command -v $pexe ; then
+		ln -s "$(command -v $pexe)" $TEST_ROOT/path
 	else
 		continue
 	fi
diff --git a/tests/test_in_vterm/test_shells.sh b/tests/test_in_vterm/test_shells.sh
index d4d0eef3..f27442ab 100755
--- a/tests/test_in_vterm/test_shells.sh
+++ b/tests/test_in_vterm/test_shells.sh
@@ -27,30 +27,30 @@ mkdir "$TEST_ROOT/fish_home/fish"
 mkdir "$TEST_ROOT/fish_home/fish/generated_completions"
 cp -r "$ROOT/tests/test_shells/ipython_home" "$TEST_ROOT"
 
-ln -s "$(which env)" "$TEST_ROOT/path"
-ln -s "$(which git)" "$TEST_ROOT/path"
-ln -s "$(which sleep)" "$TEST_ROOT/path"
-ln -s "$(which cat)" "$TEST_ROOT/path"
-ln -s "$(which false)" "$TEST_ROOT/path"
-ln -s "$(which true)" "$TEST_ROOT/path"
-ln -s "$(which kill)" "$TEST_ROOT/path"
-ln -s "$(which echo)" "$TEST_ROOT/path"
-ln -s "$(which which)" "$TEST_ROOT/path"
-ln -s "$(which dirname)" "$TEST_ROOT/path"
-ln -s "$(which wc)" "$TEST_ROOT/path"
-ln -s "$(which stty)" "$TEST_ROOT/path"
-ln -s "$(which cut)" "$TEST_ROOT/path"
-ln -s "$(which bc)" "$TEST_ROOT/path"
-ln -s "$(which expr)" "$TEST_ROOT/path"
-ln -s "$(which mktemp)" "$TEST_ROOT/path"
-ln -s "$(which grep)" "$TEST_ROOT/path"
-ln -s "$(which sed)" "$TEST_ROOT/path"
-ln -s "$(which rm)" "$TEST_ROOT/path"
-ln -s "$(which tr)" "$TEST_ROOT/path"
-ln -s "$(which uname)" "$TEST_ROOT/path"
-ln -s "$(which test)" "$TEST_ROOT/path"
-ln -s "$(which pwd)" "$TEST_ROOT/path"
-ln -s "$(which hostname)" "$TEST_ROOT/path"
+ln -s "$(command -v env)" "$TEST_ROOT/path"
+ln -s "$(command -v git)" "$TEST_ROOT/path"
+ln -s "$(command -v sleep)" "$TEST_ROOT/path"
+ln -s "$(command -v cat)" "$TEST_ROOT/path"
+ln -s "$(command -v false)" "$TEST_ROOT/path"
+ln -s "$(command -v true)" "$TEST_ROOT/path"
+ln -s "$(command -v kill)" "$TEST_ROOT/path"
+ln -s "$(command -v echo)" "$TEST_ROOT/path"
+ln -s "$(command -v which)" "$TEST_ROOT/path"
+ln -s "$(command -v dirname)" "$TEST_ROOT/path"
+ln -s "$(command -v wc)" "$TEST_ROOT/path"
+ln -s "$(command -v stty)" "$TEST_ROOT/path"
+ln -s "$(command -v cut)" "$TEST_ROOT/path"
+ln -s "$(command -v bc)" "$TEST_ROOT/path"
+ln -s "$(command -v expr)" "$TEST_ROOT/path"
+ln -s "$(command -v mktemp)" "$TEST_ROOT/path"
+ln -s "$(command -v grep)" "$TEST_ROOT/path"
+ln -s "$(command -v sed)" "$TEST_ROOT/path"
+ln -s "$(command -v rm)" "$TEST_ROOT/path"
+ln -s "$(command -v tr)" "$TEST_ROOT/path"
+ln -s "$(command -v uname)" "$TEST_ROOT/path"
+ln -s "$(command -v test)" "$TEST_ROOT/path"
+ln -s "$(command -v pwd)" "$TEST_ROOT/path"
+ln -s "$(command -v hostname)" "$TEST_ROOT/path"
 ln -s "$ROOT/tests/test_shells/bgscript.sh" "$TEST_ROOT/path"
 ln -s "$ROOT/tests/test_shells/waitpid.sh" "$TEST_ROOT/path"
 
@@ -62,8 +62,8 @@ if test -e "$ROOT/scripts/powerline" ; then
 	ln -s "$ROOT/scripts/powerline" "$TEST_ROOT/path"
 elif test -e client/powerline ; then
 	ln -s "$ROOT/client/powerline" "$TEST_ROOT/path"
-elif which powerline ; then
-	ln -s "$(which powerline)" "$TEST_ROOT/path"
+elif command -v powerline ; then
+	ln -s "$(command -v powerline)" "$TEST_ROOT/path"
 else
 	echo "Executable powerline was not found"
 	exit 1
@@ -75,9 +75,9 @@ if test "$(
 	HAS_C_CLIENT=1
 fi
 
-if which socat ; then
+if command -v socat ; then
 	HAS_SOCAT=1
-	ln -s "$(which socat)" "$TEST_ROOT/path"
+	ln -s "$(command -v socat)" "$TEST_ROOT/path"
 	ln -s "$ROOT/client/powerline.sh" "$TEST_ROOT/path"
 fi
 
@@ -97,8 +97,8 @@ test_shell() {
 		echo "Skipping test, C client not available"
 		return
 	fi
-	if which "$test_binding" ; then
-		ln -s "$(which "$test_binding")" "$TEST_ROOT/path"
+	if command -v "$test_binding" ; then
+		ln -s "$(command -v "$test_binding")" "$TEST_ROOT/path"
 	fi
 
 	if ! "${PYTHON}" "$ROOT/tests/test_in_vterm/test_shells.py" \
diff --git a/tests/test_in_vterm/test_tmux.sh b/tests/test_in_vterm/test_tmux.sh
index 062e02ba..ab4e007f 100755
--- a/tests/test_in_vterm/test_tmux.sh
+++ b/tests/test_in_vterm/test_tmux.sh
@@ -6,8 +6,8 @@ enter_suite tmux final
 
 vterm_setup
 
-ln -s "$(which env)" "$TEST_ROOT/path"
-ln -s "$(which cut)" "$TEST_ROOT/path"
+ln -s "$(command -v env)" "$TEST_ROOT/path"
+ln -s "$(command -v cut)" "$TEST_ROOT/path"
 ln -s "$ROOT/scripts/powerline-render" "$TEST_ROOT/path"
 ln -s "$ROOT/scripts/powerline-config" "$TEST_ROOT/path"
 
@@ -17,10 +17,10 @@ test_tmux() {
 		# occasionally.
 		return 0
 	fi
-	if ! which "${POWERLINE_TMUX_EXE}" ; then
+	if ! command -v "${POWERLINE_TMUX_EXE}" ; then
 		return 0
 	fi
-	ln -sf "$(which "${POWERLINE_TMUX_EXE}")" "$TEST_ROOT/path/tmux"
+	ln -sf "$(command -v "${POWERLINE_TMUX_EXE}")" "$TEST_ROOT/path/tmux"
 	f="$ROOT/tests/test_in_vterm/test_tmux.py"
 	if ! "${PYTHON}" "$f" ; then
 		local test_name="$("$POWERLINE_TMUX_EXE" -V 2>&1 | cut -d' ' -f2)"
diff --git a/tests/test_in_vterm/test_vim.sh b/tests/test_in_vterm/test_vim.sh
index a7e61686..2811e456 100755
--- a/tests/test_in_vterm/test_vim.sh
+++ b/tests/test_in_vterm/test_vim.sh
@@ -12,10 +12,10 @@ test_vim() {
 		# Can only link with cpython
 		return 0
 	fi
-	if ! which "$POWERLINE_VIM_EXE" ; then
+	if ! command -v "$POWERLINE_VIM_EXE" ; then
 		return 0
 	fi
-	ln -sf "$(which "${POWERLINE_VIM_EXE}")" "$TEST_ROOT/path/vim"
+	ln -sf "$(command -v "${POWERLINE_VIM_EXE}")" "$TEST_ROOT/path/vim"
 	f="$ROOT/tests/test_in_vterm/test_vim.py"
 	if ! "${PYTHON}" "$f" ; then
 		local test_name="$(LANG=C "$POWERLINE_VIM_EXE" --cmd 'echo version' --cmd qa 2>&1 | tail -n2)"
diff --git a/tests/test_shells/test.sh b/tests/test_shells/test.sh
index 44943029..ffeaa65e 100755
--- a/tests/test_shells/test.sh
+++ b/tests/test_shells/test.sh
@@ -120,7 +120,7 @@ do_run_test() {
 				"$TEST_ROOT/path/${SH}" --version
 				;;
 		esac
-		if which dpkg >/dev/null ; then
+		if command -v dpkg >/dev/null ; then
 			dpkg -s ${SH}
 		fi
 		return 1
@@ -167,43 +167,43 @@ mkdir "$TEST_ROOT/fish_home/fish/generated_completions"
 cp -r "$ROOT/tests/test_shells/ipython_home" "$TEST_ROOT"
 
 mkdir "$TEST_ROOT/path"
-ln -s "$(which "${PYTHON}")" "$TEST_ROOT/path/python"
-ln -s "$(which env)" "$TEST_ROOT/path"
-ln -s "$(which git)" "$TEST_ROOT/path"
-ln -s "$(which sleep)" "$TEST_ROOT/path"
-ln -s "$(which cat)" "$TEST_ROOT/path"
-ln -s "$(which false)" "$TEST_ROOT/path"
-ln -s "$(which true)" "$TEST_ROOT/path"
-ln -s "$(which kill)" "$TEST_ROOT/path"
-ln -s "$(which echo)" "$TEST_ROOT/path"
-ln -s "$(which which)" "$TEST_ROOT/path"
-ln -s "$(which dirname)" "$TEST_ROOT/path"
-ln -s "$(which wc)" "$TEST_ROOT/path"
-ln -s "$(which stty)" "$TEST_ROOT/path"
-ln -s "$(which cut)" "$TEST_ROOT/path"
-ln -s "$(which bc)" "$TEST_ROOT/path"
-ln -s "$(which expr)" "$TEST_ROOT/path"
-ln -s "$(which mktemp)" "$TEST_ROOT/path"
-ln -s "$(which grep)" "$TEST_ROOT/path"
-ln -s "$(which sed)" "$TEST_ROOT/path"
-ln -s "$(which rm)" "$TEST_ROOT/path"
-ln -s "$(which tr)" "$TEST_ROOT/path"
-ln -s "$(which uname)" "$TEST_ROOT/path"
-ln -s "$(which test)" "$TEST_ROOT/path"
-ln -s "$(which pwd)" "$TEST_ROOT/path"
-ln -s "$(which hostname)" "$TEST_ROOT/path"
+ln -s "$(command -v "${PYTHON}")" "$TEST_ROOT/path/python"
+ln -s "$(command -v env)" "$TEST_ROOT/path"
+ln -s "$(command -v git)" "$TEST_ROOT/path"
+ln -s "$(command -v sleep)" "$TEST_ROOT/path"
+ln -s "$(command -v cat)" "$TEST_ROOT/path"
+ln -s "$(command -v false)" "$TEST_ROOT/path"
+ln -s "$(command -v true)" "$TEST_ROOT/path"
+ln -s "$(command -v kill)" "$TEST_ROOT/path"
+ln -s "$(command -v echo)" "$TEST_ROOT/path"
+ln -s "$(command -v which)" "$TEST_ROOT/path"
+ln -s "$(command -v dirname)" "$TEST_ROOT/path"
+ln -s "$(command -v wc)" "$TEST_ROOT/path"
+ln -s "$(command -v stty)" "$TEST_ROOT/path"
+ln -s "$(command -v cut)" "$TEST_ROOT/path"
+ln -s "$(command -v bc)" "$TEST_ROOT/path"
+ln -s "$(command -v expr)" "$TEST_ROOT/path"
+ln -s "$(command -v mktemp)" "$TEST_ROOT/path"
+ln -s "$(command -v grep)" "$TEST_ROOT/path"
+ln -s "$(command -v sed)" "$TEST_ROOT/path"
+ln -s "$(command -v rm)" "$TEST_ROOT/path"
+ln -s "$(command -v tr)" "$TEST_ROOT/path"
+ln -s "$(command -v uname)" "$TEST_ROOT/path"
+ln -s "$(command -v test)" "$TEST_ROOT/path"
+ln -s "$(command -v pwd)" "$TEST_ROOT/path"
+ln -s "$(command -v hostname)" "$TEST_ROOT/path"
 ln -s "$ROOT/tests/test_shells/bgscript.sh" "$TEST_ROOT/path"
 ln -s "$ROOT/tests/test_shells/waitpid.sh" "$TEST_ROOT/path"
-if which socat ; then
-	ln -s "$(which socat)" "$TEST_ROOT/path"
+if command -v socat ; then
+	ln -s "$(command -v socat)" "$TEST_ROOT/path"
 fi
 for pexe in powerline powerline-config powerline-render powerline.sh powerline.py ; do
 	if test -e "$ROOT/scripts/$pexe" ; then
 		ln -s "$ROOT/scripts/$pexe" "$TEST_ROOT/path"
 	elif test -e client/$pexe ; then
 		ln -s "$ROOT/client/$pexe" "$TEST_ROOT/path"
-	elif which $pexe ; then
-		ln -s "$(which $pexe)" "$TEST_ROOT/path"
+	elif command -v $pexe ; then
+		ln -s "$(command -v $pexe)" "$TEST_ROOT/path"
 	else
 		echo "Executable $pexe was not found"
 		exit 1
@@ -216,7 +216,7 @@ ln -s python "$TEST_ROOT/path/ipython"
 IPYTHON_PYTHON=ipython
 
 if test -z "$POWERLINE_RC_EXE" ; then
-	if which rc-status >/dev/null ; then
+	if command -v rc-status >/dev/null ; then
 		# On Gentoo `rc` executable is from OpenRC. Thus app-shells/rc instals 
 		# `rcsh` executable.
 		POWERLINE_RC_EXE=rcsh
@@ -225,8 +225,8 @@ if test -z "$POWERLINE_RC_EXE" ; then
 	fi
 fi
 
-if which "$POWERLINE_RC_EXE" >/dev/null ; then
-	ln -s "$(which $POWERLINE_RC_EXE)" "$TEST_ROOT/path/rc"
+if command -v "$POWERLINE_RC_EXE" >/dev/null ; then
+	ln -s "$(command -v $POWERLINE_RC_EXE)" "$TEST_ROOT/path/rc"
 fi
 
 exes="bash zsh busybox tcsh mksh"
@@ -240,7 +240,7 @@ fi
 #exes="$exes dash"
 
 for exe in $exes ; do
-	if which $exe >/dev/null ; then
+	if command -v $exe >/dev/null ; then
 		if test "$exe" = "fish" ; then
 			fish_version="$(fish --version 2>&1)"
 			fish_version="${fish_version##* }"
@@ -268,7 +268,7 @@ for exe in $exes ; do
 				fi
 			fi
 		fi
-		ln -s "$(which $exe)" "$TEST_ROOT/path"
+		ln -s "$(command -v $exe)" "$TEST_ROOT/path"
 	fi
 done
 
@@ -351,7 +351,7 @@ if ( \
 			I="$(( I + 1 ))"
 			if test "$TEST_CLIENT" = "C" && ! test -x "$ROOT/scripts/powerline"
 			then
-				if which powerline >/dev/null ; then
+				if command -v powerline >/dev/null ; then
 					POWERLINE_COMMAND=powerline
 				else
 					continue