diff --git a/contrib/gdb-firejail.sh b/contrib/gdb-firejail.sh
index 397438e1e41..35348088e97 100755
--- a/contrib/gdb-firejail.sh
+++ b/contrib/gdb-firejail.sh
@@ -17,7 +17,7 @@ if [ -z "${1##*/firejail}" ]; then
 else
     # First argument is not named firejail, then add default unless environment
     # variable already set.
-    set -- ${FIREJAIL:=$(which firejail)} "$@"
+    set -- ${FIREJAIL:=$(command -v firejail)} "$@"
 fi
 
 bash -c "kill -STOP \$\$; exec \"\$0\" \"\$@\"" "$@" &
diff --git a/test/appimage/appimage.sh b/test/appimage/appimage.sh
index 9afacf5be5b..c2bdad012ad 100755
--- a/test/appimage/appimage.sh
+++ b/test/appimage/appimage.sh
@@ -13,7 +13,7 @@ echo "TESTING: AppImage v1 (test/appimage/appimage-v1.exp)"
 echo "TESTING: AppImage v2 (test/appimage/appimage-v2.exp)"
 ./appimage-v2.exp
 
-echo "TESTING: AppImage file name (test/appimage/filename.exp)";
+echo "TESTING: AppImage file name (test/appimage/filename.exp)"
 ./filename.exp
 
 echo "TESTING: AppImage argsv1 (test/appimage/appimage-args.exp)"
diff --git a/test/apps-x11-xorg/apps-x11-xorg.sh b/test/apps-x11-xorg/apps-x11-xorg.sh
index 9ed1239798b..9dcee7aff66 100755
--- a/test/apps-x11-xorg/apps-x11-xorg.sh
+++ b/test/apps-x11-xorg/apps-x11-xorg.sh
@@ -7,8 +7,7 @@ export MALLOC_CHECK_=3
 export MALLOC_PERTURB_=$(($RANDOM % 255 + 1))
 export LC_ALL=C
 
-which firefox 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v firefox
 then
 	echo "TESTING: firefox x11 xorg"
 	./firefox.exp
@@ -16,8 +15,7 @@ else
 	echo "TESTING SKIP: firefox not found"
 fi
 
-which transmission-gtk 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v transmission-gtk
 then
 	echo "TESTING: transmission-gtk x11 xorg"
 	./transmission-gtk.exp
@@ -25,8 +23,7 @@ else
 	echo "TESTING SKIP: transmission-gtk not found"
 fi
 
-which transmission-qt 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v transmission-qt
 then
 	echo "TESTING: transmission-qt x11 xorg"
 	./transmission-qt.exp
@@ -34,8 +31,7 @@ else
 	echo "TESTING SKIP: transmission-qt not found"
 fi
 
-which thunderbird 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v thunderbird
 then
 	echo "TESTING: thunderbird x11 xorg"
 	./thunderbird.exp
diff --git a/test/apps-x11/apps-x11.sh b/test/apps-x11/apps-x11.sh
index a3c946ca4dd..b2722eed3e5 100755
--- a/test/apps-x11/apps-x11.sh
+++ b/test/apps-x11/apps-x11.sh
@@ -10,49 +10,42 @@ export LC_ALL=C
 echo "TESTING: no x11 (test/apps-x11/x11-none.exp)"
 ./x11-none.exp
 
-
-which xterm 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v xterm
 then
 	echo "TESTING: xterm x11 xorg"
 	./xterm-xorg.exp
 
-	which xpra 2>/dev/null
-	if [ "$?" -eq 0 ];
+	if command -v xpra
 	then
-	echo "TESTING: xterm x11 xpra"
-	./xterm-xpra.exp
+		echo "TESTING: xterm x11 xpra"
+		./xterm-xpra.exp
 	fi
 
-	which Xephyr 2>/dev/null
-	if [ "$?" -eq 0 ];
+	if command -v Xephyr
 	then
-	echo "TESTING: xterm x11 xephyr"
-	./xterm-xephyr.exp
+		echo "TESTING: xterm x11 xephyr"
+		./xterm-xephyr.exp
 	fi
 else
 	echo "TESTING SKIP: xterm not found"
 fi
 
 # check xpra/xephyr
-which xpra 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v xpra
 then
-        echo "xpra found"
+	echo "xpra found"
 else
-        echo "xpra not found"
-	which Xephyr 2>/dev/null
-	if [ "$?" -eq 0 ];
+	echo "xpra not found"
+	if command -v Xephyr
 	then
-        	echo "Xephyr found"
+		echo "Xephyr found"
 	else
-        	echo "TESTING SKIP: xpra and/or Xephyr not found"
+		echo "TESTING SKIP: xpra and/or Xephyr not found"
 		exit
 	fi
 fi
 
-which firefox 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v firefox
 then
 	echo "TESTING: firefox x11"
 	./firefox.exp
@@ -60,8 +53,7 @@ else
 	echo "TESTING SKIP: firefox not found"
 fi
 
-which chromium 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v chromium
 then
 	echo "TESTING: chromium x11"
 	./chromium.exp
@@ -69,8 +61,7 @@ else
 	echo "TESTING SKIP: chromium not found"
 fi
 
-which transmission-gtk 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v transmission-gtk
 then
 	echo "TESTING: transmission-gtk x11"
 	./transmission-gtk.exp
@@ -78,8 +69,7 @@ else
 	echo "TESTING SKIP: transmission-gtk not found"
 fi
 
-which thunderbird 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v thunderbird
 then
 	echo "TESTING: thunderbird x11"
 	./thunderbird.exp
diff --git a/test/apps/apps.sh b/test/apps/apps.sh
index 83e977ba0c5..0ef01bf2efa 100755
--- a/test/apps/apps.sh
+++ b/test/apps/apps.sh
@@ -7,12 +7,10 @@ export MALLOC_CHECK_=3
 export MALLOC_PERTURB_=$(($RANDOM % 255 + 1))
 export LC_ALL=C
 
-LIST="firefox midori chromium opera transmission-qt qbittorrent uget-gtk filezilla gthumb thunderbird "
-LIST+="vlc fbreader deluge gnome-mplayer xchat wine kcalc ktorrent hexchat"
+apps=(firefox midori chromium opera transmission-qt qbittorrent uget-gtk filezilla gthumb thunderbird vlc fbreader deluge gnome-mplayer xchat wine kcalc ktorrent hexchat)
 
-for app in $LIST; do
-	which $app 2>/dev/null
-	if [ "$?" -eq 0 ];
+for app in "${apps[@]}"; do
+	if command -v "$app"
 	then
 		echo "TESTING: $app"
 		./$app.exp
diff --git a/test/chroot/chroot.sh b/test/chroot/chroot.sh
index 3c3e7311b23..f5ccf3549ba 100755
--- a/test/chroot/chroot.sh
+++ b/test/chroot/chroot.sh
@@ -17,6 +17,4 @@ echo "TESTING: chroot (test/chroot/fs_chroot.exp)"
 echo "TESTING: unchroot as root (test/chroot/unchroot-as-root.exp)"
 sudo ./unchroot-as-root.exp
 
-
-
 rm -f unchroot
diff --git a/test/compile/compile.sh b/test/compile/compile.sh
index 6b994ba7009..0285c893579 100755
--- a/test/compile/compile.sh
+++ b/test/compile/compile.sh
@@ -31,7 +31,7 @@ arr[15]="TEST 15: compile private-home disabled"
 arr[16]="TEST 16: compile disable manpages"
 arr[17]="TEST 17: disable tmpfs as regular user"
 arr[18]="TEST 18: disable private home"
-arr[18]="TEST 19: enable ids"
+arr[19]="TEST 19: enable ids"
 
 # remove previous reports and output file
 cleanup() {
@@ -47,23 +47,23 @@ print_title() {
 	echo
 	echo
 	echo "**************************************************"
-	echo $1
+	echo "$1"
 	echo "**************************************************"
 }
 
 DIST="$1"
-while [ $# -gt 0 ]; do    # Until you run out of parameters . . .
-    case "$1" in
-    --clean)
-    	cleanup
-    	exit
-	;;
-    --help)
-    	echo "./compile.sh [--clean|--help]"
-    	exit
-    	;;
-    esac
-    shift       # Check next set of parameters.
+while [[ $# -gt 0 ]]; do    # Until you run out of parameters . . .
+	case "$1" in
+	--clean)
+		cleanup
+		exit
+		;;
+	--help)
+		echo "./compile.sh [--clean|--help]"
+		exit
+		;;
+	esac
+	shift       # Check next set of parameters.
 done
 
 cleanup
@@ -76,8 +76,8 @@ cleanup
 #*****************************************************************
 print_title "${arr[1]}"
 echo "$DIST"
-tar -xJvf ../../$DIST.tar.xz
-mv $DIST firejail
+tar -xJvf ../../"$DIST.tar.xz"
+mv "$DIST" firejail
 
 cd firejail
 ./configure --prefix=/usr --enable-fatal-warnings 2>&1 | tee ../output-configure
@@ -89,7 +89,6 @@ cp output-configure oc1
 cp output-make om1
 rm output-configure output-make
 
-
 #*****************************************************************
 # TEST 2
 #*****************************************************************
@@ -98,7 +97,7 @@ rm output-configure output-make
 print_title "${arr[2]}"
 cd firejail
 make distclean
-./configure --prefix=/usr --disable-dbusproxy  --enable-fatal-warnings 2>&1 | tee ../output-configure
+./configure --prefix=/usr --disable-dbusproxy --enable-fatal-warnings 2>&1 | tee ../output-configure
 make -j4 2>&1 | tee ../output-make
 cd ..
 grep Warning output-configure output-make > ./report-test2
@@ -115,7 +114,7 @@ rm output-configure output-make
 print_title "${arr[3]}"
 cd firejail
 make distclean
-./configure --prefix=/usr --disable-chroot  --enable-fatal-warnings 2>&1 | tee ../output-configure
+./configure --prefix=/usr --disable-chroot --enable-fatal-warnings 2>&1 | tee ../output-configure
 make -j4 2>&1 | tee ../output-make
 cd ..
 grep Warning output-configure output-make > ./report-test3
@@ -132,7 +131,7 @@ rm output-configure output-make
 print_title "${arr[4]}"
 cd firejail
 make distclean
-./configure --prefix=/usr --disable-firetunnel  --enable-fatal-warnings 2>&1 | tee ../output-configure
+./configure --prefix=/usr --disable-firetunnel --enable-fatal-warnings 2>&1 | tee ../output-configure
 make -j4 2>&1 | tee ../output-make
 cd ..
 grep Warning output-configure output-make > ./report-test4
@@ -149,7 +148,7 @@ rm output-configure output-make
 print_title "${arr[5]}"
 cd firejail
 make distclean
-./configure --prefix=/usr --disable-userns  --enable-fatal-warnings 2>&1 | tee ../output-configure
+./configure --prefix=/usr --disable-userns --enable-fatal-warnings 2>&1 | tee ../output-configure
 make -j4 2>&1 | tee ../output-make
 cd ..
 grep Warning output-configure output-make > ./report-test5
@@ -167,7 +166,7 @@ rm output-configure output-make
 print_title "${arr[6]}"
 cd firejail
 make distclean
-./configure --prefix=/usr --disable-network  --enable-fatal-warnings 2>&1 | tee ../output-configure
+./configure --prefix=/usr --disable-network --enable-fatal-warnings 2>&1 | tee ../output-configure
 make -j4 2>&1 | tee ../output-make
 cd ..
 grep Warning output-configure output-make > ./report-test6
@@ -184,7 +183,7 @@ rm output-configure output-make
 print_title "${arr[7]}"
 cd firejail
 make distclean
-./configure --prefix=/usr --disable-x11  --enable-fatal-warnings 2>&1 | tee ../output-configure
+./configure --prefix=/usr --disable-x11 --enable-fatal-warnings 2>&1 | tee ../output-configure
 make -j4 2>&1 | tee ../output-make
 cd ..
 grep Warning output-configure output-make > ./report-test7
@@ -218,7 +217,7 @@ rm output-configure output-make
 print_title "${arr[9]}"
 cd firejail
 make distclean
-./configure --prefix=/usr --disable-file-transfer  --enable-fatal-warnings 2>&1 | tee ../output-configure
+./configure --prefix=/usr --disable-file-transfer --enable-fatal-warnings 2>&1 | tee ../output-configure
 make -j4 2>&1 | tee ../output-make
 cd ..
 grep Warning output-configure output-make > ./report-test9
@@ -235,7 +234,7 @@ rm output-configure output-make
 print_title "${arr[10]}"
 cd firejail
 make distclean
-./configure --prefix=/usr --disable-whitelist  --enable-fatal-warnings 2>&1 | tee ../output-configure
+./configure --prefix=/usr --disable-whitelist --enable-fatal-warnings 2>&1 | tee ../output-configure
 make -j4 2>&1 | tee ../output-make
 cd ..
 grep Warning output-configure output-make > ./report-test10
@@ -252,7 +251,7 @@ rm output-configure output-make
 print_title "${arr[11]}"
 cd firejail
 make distclean
-./configure --prefix=/usr --disable-globalcfg  --enable-fatal-warnings 2>&1 | tee ../output-configure
+./configure --prefix=/usr --disable-globalcfg --enable-fatal-warnings 2>&1 | tee ../output-configure
 make -j4 2>&1 | tee ../output-make
 cd ..
 grep Warning output-configure output-make > ./report-test11
@@ -269,7 +268,7 @@ rm output-configure output-make
 print_title "${arr[12]}"
 cd firejail
 make distclean
-./configure --prefix=/usr --enable-apparmor  --enable-fatal-warnings 2>&1 | tee ../output-configure
+./configure --prefix=/usr --enable-apparmor --enable-fatal-warnings 2>&1 | tee ../output-configure
 make -j4 2>&1 | tee ../output-make
 cd ..
 grep Warning output-configure output-make > ./report-test12
@@ -354,7 +353,7 @@ rm output-configure output-make
 print_title "${arr[17]}"
 cd firejail
 make distclean
-./configure --prefix=/usr  --disable-usertmpfs --enable-fatal-warnings 2>&1 | tee ../output-configure
+./configure --prefix=/usr --disable-usertmpfs --enable-fatal-warnings 2>&1 | tee ../output-configure
 make -j4 2>&1 | tee ../output-make
 cd ..
 grep Warning output-configure output-make > ./report-test17
@@ -410,23 +409,23 @@ echo "**********************************************************"
 
 wc -l report-test*
 echo
-echo  "Legend:"
-echo ${arr[1]}
-echo ${arr[2]}
-echo ${arr[3]}
-echo ${arr[4]}
-echo ${arr[5]}
-echo ${arr[6]}
-echo ${arr[7]}
-echo ${arr[8]}
-echo ${arr[9]}
-echo ${arr[10]}
-echo ${arr[11]}
-echo ${arr[12]}
-echo ${arr[13]}
-echo ${arr[14]}
-echo ${arr[15]}
-echo ${arr[16]}
-echo ${arr[17]}
-echo ${arr[18]}
-echo ${arr[19]}
+echo "Legend:"
+echo "${arr[1]}"
+echo "${arr[2]}"
+echo "${arr[3]}"
+echo "${arr[4]}"
+echo "${arr[5]}"
+echo "${arr[6]}"
+echo "${arr[7]}"
+echo "${arr[8]}"
+echo "${arr[9]}"
+echo "${arr[10]}"
+echo "${arr[11]}"
+echo "${arr[12]}"
+echo "${arr[13]}"
+echo "${arr[14]}"
+echo "${arr[15]}"
+echo "${arr[16]}"
+echo "${arr[17]}"
+echo "${arr[18]}"
+echo "${arr[19]}"
diff --git a/test/environment/environment.sh b/test/environment/environment.sh
index da9c170b940..c88c91741bc 100755
--- a/test/environment/environment.sh
+++ b/test/environment/environment.sh
@@ -7,7 +7,6 @@ export MALLOC_CHECK_=3
 export MALLOC_PERTURB_=$(($RANDOM % 255 + 1))
 export LC_ALL=C
 
-
 echo "TESTING: timeout (test/environment/timeout.exp)"
 ./timeout.exp
 
@@ -39,13 +38,12 @@ echo "TESTING: environment variables (test/environment/env.exp)"
 echo "TESTING: firejail in firejail - single sandbox (test/environment/firejail-in-firejail.exp)"
 ./firejail-in-firejail.exp
 
-which aplay 2>/dev/null
-if [ "$?" -eq 0 ] && [ "$(aplay -l | grep -c "List of PLAYBACK")" -gt 0 ];
+if command -v aplay && [[ $(aplay -l | grep -c "List of PLAYBACK") -gt 0 ]]
 then
-        echo "TESTING: sound (test/environment/sound.exp)"
-        ./sound.exp
+	echo "TESTING: sound (test/environment/sound.exp)"
+	./sound.exp
 else
-        echo "TESTING SKIP: no aplay or sound card found"
+	echo "TESTING SKIP: no aplay or sound card found"
 fi
 
 echo "TESTING: nice (test/environment/nice.exp)"
@@ -54,26 +52,24 @@ echo "TESTING: nice (test/environment/nice.exp)"
 echo "TESTING: quiet (test/environment/quiet.exp)"
 ./quiet.exp
 
-which strace 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v strace
 then
-        echo "TESTING: --allow-debuggers (test/environment/allow-debuggers.exp)"
-        ./allow-debuggers.exp
+	echo "TESTING: --allow-debuggers (test/environment/allow-debuggers.exp)"
+	./allow-debuggers.exp
 else
-        echo "TESTING SKIP: strace not found"
+	echo "TESTING SKIP: strace not found"
 fi
 
 # to install ibus:
 #       $ sudo apt-get install ibus-table-array30
 #       $ ibus-setup
 
-find ~/.config/ibus/bus | grep unix-0
-if [ "$?" -eq 0 ];
+if find ~/.config/ibus/bus | grep unix-0
 then
 	echo "TESTING: ibus (test/environment/ibus.exp)"
 	./ibus.exp
 else
-        echo "TESTING SKIP: ibus not configured"
+	echo "TESTING SKIP: ibus not configured"
 fi
 
 echo "TESTING: rlimit (test/environment/rlimit.exp)"
diff --git a/test/environment/output.sh b/test/environment/output.sh
index 329cb40c732..ba06f918410 100755
--- a/test/environment/output.sh
+++ b/test/environment/output.sh
@@ -5,8 +5,8 @@
 
 i="0"
 
-while  [ $i -lt 150000 ]
+while [[ $i -lt 150000 ]]
 do
-	echo message number $i
-	i=$[$i+1]
+	echo "message number $i"
+	i=$((i+1))
 done
diff --git a/test/fcopy/fcopy.sh b/test/fcopy/fcopy.sh
index fca599889f2..72b87d14cfe 100755
--- a/test/fcopy/fcopy.sh
+++ b/test/fcopy/fcopy.sh
@@ -7,7 +7,7 @@ export MALLOC_CHECK_=3
 export MALLOC_PERTURB_=$(($RANDOM % 255 + 1))
 export LC_ALL=C
 
-if [ -f /etc/debian_version ]; then
+if [[ -f /etc/debian_version ]]; then
 	libdir=$(dirname "$(dpkg -L firejail | grep fcopy)")
 	export PATH="$PATH:$libdir"
 fi
@@ -29,4 +29,4 @@ echo "TESTING: fcopy directory (test/fcopy/dircopy.exp)"
 ./dircopy.exp
 
 rm -fr dest/*
-rm -f src/dircopy.exp
\ No newline at end of file
+rm -f src/dircopy.exp
diff --git a/test/features/test.sh b/test/features/test.sh
index b507c6d3773..44677aaa783 100755
--- a/test/features/test.sh
+++ b/test/features/test.sh
@@ -8,28 +8,25 @@ OVERLAY="overlay"
 CHROOT="chroot"
 NETWORK="network"
 
-while [ $# -gt 0 ]; do    # Until you run out of parameters . . .
-    case "$1" in
-    --nooverlay)
-    	OVERLAY="none"
-	;;
-    --nochroot)
-    	CHROOT="none"
-	;;
-    --nonetwork)
-        NETWORK="none"
-        ;;
-    --help)
-    	echo "./test.sh [--nooverlay|--nochroot|--nonetwork|--help] | grep TESTING"
-    	exit
-    	;;
-    esac
-    shift       # Check next set of parameters.
+while [[ $# -gt 0 ]]; do    # Until you run out of parameters . . .
+	case "$1" in
+	--nooverlay)
+		OVERLAY="none"
+		;;
+	--nochroot)
+		CHROOT="none"
+		;;
+	--nonetwork)
+		NETWORK="none"
+		;;
+	--help)
+		echo "./test.sh [--nooverlay|--nochroot|--nonetwork|--help] | grep TESTING"
+		exit
+		;;
+	esac
+	shift       # Check next set of parameters.
 done
 
-
-
-
 #
 # Feature testing
 #
@@ -38,85 +35,85 @@ done
 # Default features
 ####################
 echo "TESTING: 1.1 disable /boot"
-./1.1.exp $OVERLAY $CHROOT
+./1.1.exp "$OVERLAY" "$CHROOT"
 
 echo "TESTING: 1.2 new /proc"
-./1.2.exp $OVERLAY $CHROOT
+./1.2.exp "$OVERLAY" "$CHROOT"
 
 echo "TESTING: 1.4 mask other users"
-./1.4.exp $OVERLAY $CHROOT
+./1.4.exp "$OVERLAY" "$CHROOT"
 
 echo "TESTING: 1.5 PID namespace"
-./1.5.exp $OVERLAY $CHROOT
+./1.5.exp "$OVERLAY" "$CHROOT"
 
 echo "TESTING: 1.6 new /var/log"
-./1.6.exp $OVERLAY $CHROOT
+./1.6.exp "$OVERLAY" "$CHROOT"
 
 echo "TESTING: 1.7 new /var/tmp"
-./1.7.exp $OVERLAY $CHROOT
+./1.7.exp "$OVERLAY" "$CHROOT"
 
 echo "TESTING: 1.8 disable firejail config and run time information"
-./1.8.exp $OVERLAY $CHROOT
+./1.8.exp "$OVERLAY" "$CHROOT"
 
 echo "TESTING: 1.10 disable /selinux"
-./1.10.exp $OVERLAY $CHROOT
+./1.10.exp "$OVERLAY" "$CHROOT"
 
 ####################
 # networking features
 ####################
-if [ $NETWORK == "network" ]
+if [[ $NETWORK == "network" ]]
 then
 	echo "TESTING: 2.1 hostname"
-	./2.1.exp $OVERLAY $CHROOT
+	./2.1.exp "$OVERLAY" "$CHROOT"
 
 	echo "TESTING: 2.2 DNS"
-	./2.2.exp $OVERLAY $CHROOT
+	./2.2.exp "$OVERLAY" "$CHROOT"
 
 	echo "TESTING: 2.3 mac-vlan"
-	./2.3.exp $OVERLAY $CHROOT
+	./2.3.exp "$OVERLAY" "$CHROOT"
 
 	echo "TESTING: 2.4 bridge"
-	./2.4.exp $OVERLAY $CHROOT
+	./2.4.exp "$OVERLAY" "$CHROOT"
 
 	echo "TESTING: 2.5 interface"
-	./2.5.exp $OVERLAY $CHROOT
+	./2.5.exp "$OVERLAY" "$CHROOT"
 
 	echo "TESTING: 2.6 Default gateway"
-	./2.6.exp $OVERLAY $CHROOT
+	./2.6.exp "$OVERLAY" "$CHROOT"
 fi
 
 ####################
 # filesystem features
 ####################
 echo "TESTING: 3.1 private (fails on OpenSUSE)"
-./3.1.exp $OVERLAY $CHROOT
+./3.1.exp "$OVERLAY" "$CHROOT"
 
 echo "TESTING: 3.2 read-only"
-./3.2.exp $OVERLAY $CHROOT
+./3.2.exp "$OVERLAY" "$CHROOT"
 
 echo "TESTING: 3.3 blacklist"
-./3.3.exp $OVERLAY $CHROOT
+./3.3.exp "$OVERLAY" "$CHROOT"
 
 echo "TESTING: 3.4 whitelist home (fails on OpenSUSE)"
-./3.4.exp $OVERLAY $CHROOT
+./3.4.exp "$OVERLAY" "$CHROOT"
 
 echo "TESTING: 3.5 private-dev"
-./3.5.exp $OVERLAY $CHROOT
+./3.5.exp "$OVERLAY" "$CHROOT"
 
 echo "TESTING: 3.6 private-etc"
-./3.6.exp notworking $CHROOT
+./3.6.exp notworking "$CHROOT"
 
 echo "TESTING: 3.7 private-tmp"
-./3.7.exp $OVERLAY $CHROOT
+./3.7.exp "$OVERLAY" "$CHROOT"
 
 echo "TESTING: 3.8 private-bin"
 ./3.8.exp notworking notworking
 
 echo "TESTING: 3.9 whitelist dev"
-./3.9.exp $OVERLAY $CHROOT
+./3.9.exp "$OVERLAY" "$CHROOT"
 
 echo "TESTING: 3.10 whitelist tmp"
-./3.10.exp $OVERLAY $CHROOT
+./3.10.exp "$OVERLAY" "$CHROOT"
 
 echo "TESTING: 3.11 mkdir"
-./3.11.exp $OVERLAY $CHROOT
+./3.11.exp "$OVERLAY" "$CHROOT"
diff --git a/test/filters/filters.sh b/test/filters/filters.sh
index 04d7080d68d..3b4a6b4923d 100755
--- a/test/filters/filters.sh
+++ b/test/filters/filters.sh
@@ -7,37 +7,37 @@ export MALLOC_CHECK_=3
 export MALLOC_PERTURB_=$(($RANDOM % 255 + 1))
 export LC_ALL=C
 
-if [ -f /etc/debian_version ]; then
+if [[ -f /etc/debian_version ]]; then
 	libdir=$(dirname "$(dpkg -L firejail | grep fseccomp)")
 	export PATH="$PATH:$libdir"
 fi
 export PATH="$PATH:/usr/lib/firejail:/usr/lib64/firejail"
 
-if [ -f /sys/kernel/security/apparmor/profiles ]; then
+if [[ -f /sys/kernel/security/apparmor/profiles ]]; then
 	echo "TESTING: apparmor (test/filters/apparmor.exp)"
 	./apparmor.exp
 else
 	echo "TESTING SKIP: no apparmor support in Linux kernel (test/filters/apparmor.exp)"
 fi
 
-if [ "$(uname -m)" = "x86_64" ]; then
-    echo "TESTING: memory-deny-write-execute (test/filters/memwrexe.exp)"
-    ./memwrexe.exp
-elif [ "$(uname -m)" = "i686" ]; then
-    echo "TESTING: memory-deny-write-execute (test/filters/memwrexe-32.exp)"
-    ./memwrexe-32.exp
+if [[ $(uname -m) == "x86_64" ]]; then
+	echo "TESTING: memory-deny-write-execute (test/filters/memwrexe.exp)"
+	./memwrexe.exp
+elif [[ $(uname -m) == "i686" ]]; then
+	echo "TESTING: memory-deny-write-execute (test/filters/memwrexe-32.exp)"
+	./memwrexe-32.exp
 else
-    echo "TESTING SKIP: memwrexe binary only running on x86_64 and i686."
+	echo "TESTING SKIP: memwrexe binary only running on x86_64 and i686."
 fi
 
 echo "TESTING: debug options (test/filters/debug.exp)"
 ./debug.exp
 
-if [ "$(uname -m)" = "x86_64" ]; then
-    echo "TESTING: seccomp run files (test/filters/seccomp-run-files.exp)"
-    ./seccomp-run-files.exp
+if [[ $(uname -m) == "x86_64" ]]; then
+	echo "TESTING: seccomp run files (test/filters/seccomp-run-files.exp)"
+	./seccomp-run-files.exp
 else
-    echo "TESTING SKIP: seccomp-run-files test implemented only for x86_64."
+	echo "TESTING SKIP: seccomp-run-files test implemented only for x86_64."
 fi
 
 echo "TESTING: seccomp postexec (test/filters/seccomp-postexec.exp)"
@@ -61,33 +61,33 @@ echo "TESTING: capabilities join (test/filters/caps-join.exp)"
 ./caps-join.exp
 
 rm -f seccomp-test-file
-if [ "$(uname -m)" = "x86_64" ]; then
-       echo "TESTING: fseccomp (test/filters/fseccomp.exp)"
-        ./fseccomp.exp
+if [[ $(uname -m) == "x86_64" ]]; then
+	echo "TESTING: fseccomp (test/filters/fseccomp.exp)"
+	./fseccomp.exp
 else
-        echo "TESTING SKIP: fseccomp test implemented only for x86_64"
+	echo "TESTING SKIP: fseccomp test implemented only for x86_64"
 fi
 rm -f seccomp-test-file
 
 
-if [ "$(uname -m)" = "x86_64" ]; then
-        echo "TESTING: protocol (test/filters/protocol.exp)"
-        ./protocol.exp
+if [[ $(uname -m) == "x86_64" ]]; then
+	echo "TESTING: protocol (test/filters/protocol.exp)"
+	./protocol.exp
 else
-        echo "TESTING SKIP: protocol, running only on x86_64"
+	echo "TESTING SKIP: protocol, running only on x86_64"
 fi
 
 echo "TESTING: seccomp bad empty (test/filters/seccomp-bad-empty.exp)"
 ./seccomp-bad-empty.exp
 
-if [ "$(uname -m)" = "x86_64" ]; then
-	echo "TESTING: seccomp debug  (test/filters/seccomp-debug.exp)"
+if [[ $(uname -m) == "x86_64" ]]; then
+	echo "TESTING: seccomp debug (test/filters/seccomp-debug.exp)"
 	./seccomp-debug.exp
-elif [ "$(uname -m)" = "i686" ]; then
-	echo "TESTING: seccomp debug  (test/filters/seccomp-debug-32.exp)"
+elif [[ $(uname -m) == "i686" ]]; then
+	echo "TESTING: seccomp debug (test/filters/seccomp-debug-32.exp)"
 	./seccomp-debug-32.exp
 else
-        echo "TESTING SKIP: protocol, running only on x86_64 and i686"
+	echo "TESTING SKIP: protocol, running only on x86_64 and i686"
 fi
 
 echo "TESTING: seccomp errno (test/filters/seccomp-errno.exp)"
@@ -96,12 +96,11 @@ echo "TESTING: seccomp errno (test/filters/seccomp-errno.exp)"
 echo "TESTING: seccomp su (test/filters/seccomp-su.exp)"
 ./seccomp-su.exp
 
-which strace 2>/dev/null
-if [ $? -eq 0 ]; then
-        echo "TESTING: seccomp ptrace (test/filters/seccomp-ptrace.exp)"
-        ./seccomp-ptrace.exp
+if command -v strace; then
+	echo "TESTING: seccomp ptrace (test/filters/seccomp-ptrace.exp)"
+	./seccomp-ptrace.exp
 else
-        echo "TESTING SKIP: ptrace, strace not found"
+	echo "TESTING SKIP: ptrace, strace not found"
 fi
 
 echo "TESTING: seccomp chmod - seccomp lists (test/filters/seccomp-chmod.exp)"
@@ -115,16 +114,16 @@ echo "TESTING: seccomp chmod profile - seccomp lists (test/filters/seccomp-chmod
 echo "TESTING: seccomp empty (test/filters/seccomp-empty.exp)"
 ./seccomp-empty.exp
 
-if [ "$(uname -m)" = "x86_64" ]; then
-    echo "TESTING: seccomp numeric (test/filters/seccomp-numeric.exp)"
-    ./seccomp-numeric.exp
+if [[ $(uname -m) == "x86_64" ]]; then
+	echo "TESTING: seccomp numeric (test/filters/seccomp-numeric.exp)"
+	./seccomp-numeric.exp
 else
-        echo "TESTING SKIP: seccomp numeric test implemented only for x86_64"
+	echo "TESTING SKIP: seccomp numeric test implemented only for x86_64"
 fi
 
-if [ "$(uname -m)" = "x86_64" ]; then
-       echo "TESTING: seccomp join (test/filters/seccomp-join.exp)"
-        ./seccomp-join.exp
+if [[ $(uname -m) == "x86_64" ]]; then
+	echo "TESTING: seccomp join (test/filters/seccomp-join.exp)"
+	./seccomp-join.exp
 else
-        echo "TESTING SKIP: seccomp join test implemented only for x86_64"
+	echo "TESTING SKIP: seccomp join test implemented only for x86_64"
 fi
diff --git a/test/fnetfilter/fnetfilter.sh b/test/fnetfilter/fnetfilter.sh
index 9ad822753a1..52f9212328f 100755
--- a/test/fnetfilter/fnetfilter.sh
+++ b/test/fnetfilter/fnetfilter.sh
@@ -7,7 +7,7 @@ export MALLOC_CHECK_=3
 export MALLOC_PERTURB_=$(($RANDOM % 255 + 1))
 export LC_ALL=C
 
-if [ -f /etc/debian_version ]; then
+if [[ -f /etc/debian_version ]]; then
 	libdir=$(dirname "$(dpkg -L firejail | grep fcopy)")
 	export PATH="$PATH:$libdir"
 fi
diff --git a/test/fs/fs.sh b/test/fs/fs.sh
index 36ff3093406..697c86d3df5 100755
--- a/test/fs/fs.sh
+++ b/test/fs/fs.sh
@@ -34,7 +34,7 @@ rm -f ~/_firejail_test_dir
 echo "TESTING: /sys/fs access (test/fs/sys_fs.exp)"
 ./sys_fs.exp
 
-if [ -c /dev/kmsg ]; then
+if [[ -c /dev/kmsg ]]; then
 	echo "TESTING: kmsg access (test/fs/kmsg.exp)"
 	./kmsg.exp
 else
@@ -45,27 +45,27 @@ echo "TESTING: read/write /var/tmp (test/fs/fs_var_tmp.exp)"
 ./fs_var_tmp.exp
 rm -f /var/tmp/_firejail_test_file
 
-if [ "$(uname -m)" = "x86_64" ]; then
-    fjconfig=/etc/firejail/firejail.config
-    printf 'private-lib yes\n' | sudo tee -a "$fjconfig" >/dev/null
-    echo "TESTING: private-lib (test/fs/private-lib.exp)"
-    ./private-lib.exp
-    printf '%s\n' "$(sed '/^private-lib yes$/d' "$fjconfig")" |
-      sudo tee "$fjconfig" >/dev/null
+if [[ $(uname -m) == "x86_64" ]]; then
+	fjconfig=/etc/firejail/firejail.config
+	printf 'private-lib yes\n' | sudo tee -a "$fjconfig" >/dev/null
+	echo "TESTING: private-lib (test/fs/private-lib.exp)"
+	./private-lib.exp
+	printf '%s\n' "$(sed '/^private-lib yes$/d' "$fjconfig")" |
+		sudo tee "$fjconfig" >/dev/null
 else
-    echo "TESTING SKIP: private-lib test implemented only for x86_64."
+	echo "TESTING SKIP: private-lib test implemented only for x86_64."
 fi
 
 echo "TESTING: read/write /var/lock (test/fs/fs_var_lock.exp)"
 ./fs_var_lock.exp
 rm -f /var/lock/_firejail_test_file
 
-if [ -w /dev/shm ]; then
-    echo "TESTING: read/write /dev/shm (test/fs/fs_dev_shm.exp)"
-    ./fs_dev_shm.exp
-    rm -f /dev/shm/_firejail_test_file
+if [[ -w /dev/shm ]]; then
+	echo "TESTING: read/write /dev/shm (test/fs/fs_dev_shm.exp)"
+	./fs_dev_shm.exp
+	rm -f /dev/shm/_firejail_test_file
 else
-    echo "TESTING SKIP: /dev/shm not writable"
+	echo "TESTING SKIP: /dev/shm not writable"
 fi
 
 echo "TESTING: private (test/fs/private.exp)"
diff --git a/test/overlay/overlay.sh b/test/overlay/overlay.sh
index 490b180e1fa..a0519d1ad64 100755
--- a/test/overlay/overlay.sh
+++ b/test/overlay/overlay.sh
@@ -22,8 +22,7 @@ rm -fr ~/_firejail_test_*
 ./fs-tmpfs.exp
 rm -fr ~/_firejail_test_*
 
-which firefox 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v firefox
 then
 	echo "TESTING: overlay firefox"
 	./firefox.exp
@@ -31,8 +30,7 @@ else
 	echo "TESTING SKIP: firefox not found"
 fi
 
-which firefox 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v firefox
 then
 	echo "TESTING: overlay firefox x11 xorg"
 	./firefox.exp
@@ -40,26 +38,22 @@ else
 	echo "TESTING SKIP: firefox not found"
 fi
 
-
 # check xpra/xephyr
-which xpra 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v xpra
 then
-        echo "xpra found"
+	echo "xpra found"
 else
-        echo "xpra not found"
-	which Xephyr 2>/dev/null
-	if [ "$?" -eq 0 ];
+	echo "xpra not found"
+	if command -v Xephyr
 	then
-        	echo "Xephyr found"
+		echo "Xephyr found"
 	else
-        	echo "TESTING SKIP: xpra and/or Xephyr not found"
+		echo "TESTING SKIP: xpra and/or Xephyr not found"
 		exit
 	fi
 fi
 
-which firefox 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v firefox
 then
 	echo "TESTING: overlay firefox x11"
 	./firefox-x11.exp
diff --git a/test/private-lib/private-lib.sh b/test/private-lib/private-lib.sh
index d168c2b1b40..6b7d433c832 100755
--- a/test/private-lib/private-lib.sh
+++ b/test/private-lib/private-lib.sh
@@ -7,12 +7,10 @@ export MALLOC_CHECK_=3g
 export MALLOC_PERTURB_=$(($RANDOM % 255 + 1))
 export LC_ALL=C
 
-LIST="gnome-logs gnome-system-log gnome-nettool pavucontrol dig evince whois galculator gnome-calculator gedit leafpad mousepad pluma transmission-gtk xcalc atril gpicview eom eog"
+apps=(gnome-logs gnome-system-log gnome-nettool pavucontrol dig evince whois galculator gnome-calculator gedit leafpad mousepad pluma transmission-gtk xcalc atril gpicview eom eog)
 
-
-for app in $LIST; do
-	which $app 2>/dev/null
-	if [ "$?" -eq 0 ];
+for app in "${apps[@]}"; do
+	if command -v "$app"
 	then
 		echo "TESTING: private-lib $app"
 		./$app.exp
diff --git a/test/profiles/all-profiles.sh b/test/profiles/all-profiles.sh
index cc17b6b00bf..a550afe2361 100755
--- a/test/profiles/all-profiles.sh
+++ b/test/profiles/all-profiles.sh
@@ -37,11 +37,11 @@ echo "TESTING: profile read-only links (test/profiles/profile_readonly.exp)"
 echo "TESTING: profile no permissions (test/profiles/profile_noperm.exp)"
 ./profile_noperm.exp
 
-PROFILES=`ls /etc/firejail/*.profile`
+profiles=( /etc/firejail/*.profile )
 echo "TESTING: default profiles installed in /etc"
 
-for PROFILE in $PROFILES
+for profile in "${profiles[@]}"
 do
-	echo "TESTING: $PROFILE"
-	./test-profile.exp $PROFILE
+	echo "TESTING: $profile"
+	./test-profile.exp "$profile"
 done
diff --git a/test/profiles/profiles.sh b/test/profiles/profiles.sh
index 8808bc9d2f6..90c88aaf5e7 100755
--- a/test/profiles/profiles.sh
+++ b/test/profiles/profiles.sh
@@ -37,11 +37,11 @@ echo "TESTING: profile read-only links (test/profiles/profile_readonly.exp)"
 echo "TESTING: profile no permissions (test/profiles/profile_noperm.exp)"
 ./profile_noperm.exp
 
-PROFILES=`ls /etc/firejail/transmission*.profile /etc/firejail/fi*.profile /etc/firejail/fl*.profile /etc/firejail/free*.profile`
+profiles=( /etc/firejail/transmission*.profile /etc/firejail/fi*.profile /etc/firejail/fl*.profile /etc/firejail/free*.profile )
 echo "TESTING: small number of default profiles installed in /etc"
 
-for PROFILE in $PROFILES
+for profile in "${profiles[@]}"
 do
-	echo "TESTING: $PROFILE"
-	./test-profile.exp $PROFILE
+	echo "TESTING: $profile"
+	./test-profile.exp "$profile"
 done
diff --git a/test/root/root.sh b/test/root/root.sh
index e8c0ec1ac3a..a39525b6ea7 100755
--- a/test/root/root.sh
+++ b/test/root/root.sh
@@ -11,8 +11,7 @@ export LC_ALL=C
 #********************************
 # firecfg
 #********************************
-which less 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v less
 then
 	echo "TESTING: firecfg (test/root/firecfg.exp)"
 	mv /home/netblue/.local/share/applications /home/netblue/.local/share/applications-store
@@ -25,24 +24,24 @@ fi
 #********************************
 # servers
 #********************************
-if [ -f /etc/init.d/snmpd ]
+if [[ -f /etc/init.d/snmpd ]]
 then
 	echo "TESTING: snmpd (test/root/snmpd.exp)"
 	./snmpd.exp
 else
-	echo "TESTING SKIP: snmpd  not found"
+	echo "TESTING SKIP: snmpd not found"
 fi
 
 
-if [ -f /etc/init.d/apache2 ]
+if [[ -f /etc/init.d/apache2 ]]
 then
 	echo "TESTING: apache2 (test/root/apache2.exp)"
 	./apache2.exp
 else
-	echo "TESTING SKIP: apache2  not found"
+	echo "TESTING SKIP: apache2 not found"
 fi
 
-if [ -f /etc/init.d/isc-dhcp-server ]
+if [[ -f /etc/init.d/isc-dhcp-server ]]
 then
 	echo "TESTING: isc dhcp server (test/root/isc-dhscp.exp)"
 	./isc-dhcp.exp
@@ -50,20 +49,20 @@ else
 	echo "TESTING SKIP: isc dhcp server not found"
 fi
 
-if [ -f /etc/init.d/unbound ]
+if [[ -f /etc/init.d/unbound ]]
 then
 	echo "TESTING: unbound (test/root/unbound.exp)"
 	./unbound.exp
 else
-	echo "TESTING SKIP: unbound  not found"
+	echo "TESTING SKIP: unbound not found"
 fi
 
-if [ -f /etc/init.d/nginx ]
+if [[ -f /etc/init.d/nginx ]]
 then
 	echo "TESTING: nginx (test/root/nginx.exp)"
 	./nginx.exp
 else
-	echo "TESTING SKIP: nginx  not found"
+	echo "TESTING SKIP: nginx not found"
 fi
 
 #********************************
diff --git a/test/stress/stress.sh b/test/stress/stress.sh
index 675cb06144e..2b4d8147d0c 100755
--- a/test/stress/stress.sh
+++ b/test/stress/stress.sh
@@ -14,7 +14,7 @@ mkdir ~/fj-stress-test
 rm blacklist.profile
 rm noblacklist.profile
 rm env.profile
-for i in `seq 1 100`;
+for i in {1..100}
 do
 	echo "hello" > ~/fj-stress-test/testfile$i
 	echo "blacklist ~/fj-stress-test/testfile$i" >> blacklist.profile
diff --git a/test/sysutils/sysutils.sh b/test/sysutils/sysutils.sh
index a903c7c6bb3..bfe7230473d 100755
--- a/test/sysutils/sysutils.sh
+++ b/test/sysutils/sysutils.sh
@@ -7,8 +7,7 @@ export MALLOC_CHECK_=3
 export MALLOC_PERTURB_=$(($RANDOM % 255 + 1))
 export LC_ALL=C
 
-which cpio 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v cpio
 then
 	echo "TESTING: cpio"
 	./cpio.exp
@@ -16,8 +15,7 @@ else
 	echo "TESTING SKIP: cpio not found"
 fi
 
-#which strings
-#if [ "$?" -eq 0 ];
+#if command -v strings
 #then
 #	echo "TESTING: strings"
 #	./strings.exp
@@ -25,8 +23,7 @@ fi
 #	echo "TESTING SKIP: strings not found"
 #fi
 
-which gzip 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v gzip
 then
 	echo "TESTING: gzip"
 	./gzip.exp
@@ -34,8 +31,7 @@ else
 	echo "TESTING SKIP: gzip not found"
 fi
 
-which xzdec 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v xzdec
 then
 	echo "TESTING: xzdec"
 	./xzdec.exp
@@ -43,8 +39,7 @@ else
 	echo "TESTING SKIP: xzdec not found"
 fi
 
-which xz 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v xz
 then
 	echo "TESTING: xz"
 	./xz.exp
@@ -52,8 +47,7 @@ else
 	echo "TESTING SKIP: xz not found"
 fi
 
-which less 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v less
 then
 	echo "TESTING: less"
 	./less.exp
@@ -61,8 +55,7 @@ else
 	echo "TESTING SKIP: less not found"
 fi
 
-which file 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v file
 then
 	echo "TESTING: file"
 	./file.exp
@@ -70,8 +63,7 @@ else
 	echo "TESTING SKIP: file not found"
 fi
 
-which tar 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v tar
 then
 	echo "TESTING: tar"
 	./tar.exp
@@ -79,8 +71,7 @@ else
 	echo "TESTING SKIP: tar not found"
 fi
 
-which ping 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v ping
 then
 	echo "TESTING: ping"
 	./ping.exp
diff --git a/test/utils/catchsignal.sh b/test/utils/catchsignal.sh
index 11717914340..cef00b2a51d 100755
--- a/test/utils/catchsignal.sh
+++ b/test/utils/catchsignal.sh
@@ -4,20 +4,20 @@
 # License GPL v2
 
 _term() {
-  echo "Caught Signal"
-  echo 1
-  sleep 1
-  echo 2
-  sleep 1
-  echo 3
-  sleep 1
-  echo 4
-  sleep 1
-  echo 5
-  sleep 1
+	echo "Caught Signal"
+	echo 1
+	sleep 1
+	echo 2
+	sleep 1
+	echo 3
+	sleep 1
+	echo 4
+	sleep 1
+	echo 5
+	sleep 1
 
-  kill $pid
-  exit
+	kill $pid
+	exit
 }
 
 trap _term SIGTERM
diff --git a/test/utils/catchsignal2.sh b/test/utils/catchsignal2.sh
index 1bd7852cdbf..21f29943013 100755
--- a/test/utils/catchsignal2.sh
+++ b/test/utils/catchsignal2.sh
@@ -4,42 +4,42 @@
 # License GPL v2
 
 _term() {
-  echo "Caught Signal"
-  echo 1
-  sleep 1
-  echo 2
-  sleep 1
-  echo 3
-  sleep 1
-  echo 4
-  sleep 1
-  echo 5
-  sleep 1
+	echo "Caught Signal"
+	echo 1
+	sleep 1
+	echo 2
+	sleep 1
+	echo 3
+	sleep 1
+	echo 4
+	sleep 1
+	echo 5
+	sleep 1
 
-  echo 10
-  sleep 1
-  echo 20
-  sleep 1
-  echo 30
-  sleep 1
-  echo 40
-  sleep 1
-  echo 50
-  sleep 1
+	echo 10
+	sleep 1
+	echo 20
+	sleep 1
+	echo 30
+	sleep 1
+	echo 40
+	sleep 1
+	echo 50
+	sleep 1
 
-  echo 100
-  sleep 1
-  echo 200
-  sleep 1
-  echo 300
-  sleep 1
-  echo 400
-  sleep 1
-  echo 500
-  sleep 1
+	echo 100
+	sleep 1
+	echo 200
+	sleep 1
+	echo 300
+	sleep 1
+	echo 400
+	sleep 1
+	echo 500
+	sleep 1
 
-  kill $pid
-  exit
+	kill $pid
+	exit
 }
 
 trap _term SIGTERM
diff --git a/test/utils/utils.sh b/test/utils/utils.sh
index 102c8df1775..647cbfb341e 100755
--- a/test/utils/utils.sh
+++ b/test/utils/utils.sh
@@ -7,7 +7,7 @@ export MALLOC_CHECK_=3
 export MALLOC_PERTURB_=$(($RANDOM % 255 + 1))
 export LC_ALL=C
 
-if [ -f /etc/debian_version ]; then
+if [[ -f /etc/debian_version ]]; then
 	libdir=$(dirname "$(dpkg -L firejail | grep fcopy)")
 	export PATH="$PATH:$libdir"
 fi
@@ -33,13 +33,12 @@ echo "TESTING: version (test/utils/version.exp)"
 echo "TESTING: help (test/utils/help.exp)"
 ./help.exp
 
-which man 2>/dev/null
-if [ "$?" -eq 0 ];
+if command -v man
 then
-        echo "TESTING: man (test/utils/man.exp)"
-        ./man.exp
+	echo "TESTING: man (test/utils/man.exp)"
+	./man.exp
 else
-        echo "TESTING SKIP: man not found"
+	echo "TESTING SKIP: man not found"
 fi
 
 echo "TESTING: list (test/utils/list.exp)"
@@ -48,12 +47,12 @@ echo "TESTING: list (test/utils/list.exp)"
 echo "TESTING: tree (test/utils/tree.exp)"
 ./tree.exp
 
-if [ $(grep -c ^processor /proc/cpuinfo) -gt 1 ];
+if [[ $(grep -c ^processor /proc/cpuinfo) -gt 1 ]]
 then
-        echo "TESTING: cpu.print (test/utils/cpu-print.exp)"
-        ./cpu-print.exp
+	echo "TESTING: cpu.print (test/utils/cpu-print.exp)"
+	./cpu-print.exp
 else
-        echo "TESTING SKIP: cpu.print, not enough CPUs"
+	echo "TESTING SKIP: cpu.print, not enough CPUs"
 fi
 
 echo "TESTING: fs.print (test/utils/fs-print.exp)"