diff --git a/all_shells.sh b/all_shells.sh
deleted file mode 100755
index 68914ba..0000000
--- a/all_shells.sh
+++ /dev/null
@@ -1,6 +0,0 @@
-#!/bin/sh
-
-for sh in /bin/dash /bin/bash /bin/ksh /bin/mksh /bin/pdksh; do
-    echo Using $sh
-    $sh "$@" || exit $?
-done
diff --git a/git-test b/git-test
index f10a0bc..e79b024 100755
--- a/git-test
+++ b/git-test
@@ -18,11 +18,11 @@ set -e
 
 VERSION=1.0.2
 
-NONGIT_OK=Yes
-SUBDIRECTORY_OK=Yes
-OPTIONS_KEEPDASHDASH=
-OPTIONS_STUCKLONG=t
-OPTIONS_SPEC="\
+export NONGIT_OK=Yes
+export SUBDIRECTORY_OK=Yes
+export OPTIONS_KEEPDASHDASH=
+export OPTIONS_STUCKLONG=t
+export OPTIONS_SPEC="\
 git test [options] [refs...]
 
 git test --clear [refs...]
@@ -96,7 +96,7 @@ progress () {
     else
 	if [ -z "$GIT_QUIET" ]; then
 	    if [ -n "$verbose" ] ; then
-		printf "$CR" 1>& $ERR
+		printf "%s" "$CR" 1>& $ERR
 	    fi
             printf "%04d | %s | %s | " \
                    "$iteration" "$short" "$small" 1>& $OUT
@@ -107,12 +107,9 @@ progress () {
 }
 
 
-second_word() {
-    echo $2
-}
-
 tree_of_commit() {
-    second_word $(git cat-file -p "$1" | grep tree)
+    words=( $(git cat-file -p "$1" | grep tree) )
+    printf "%s" "${words[1]}"
 }
 
 make_output_dirs() {
@@ -303,7 +300,7 @@ run_tests() {
 
 	link_result
 
-	iteration=$(expr $iteration + 1)
+	iteration=$((iteration + 1))
     done
 }
 
@@ -429,8 +426,8 @@ if [ $action = clear ] ; then
     if test -z "$*" ; then
 	rm -f "$cache"/*_fail "$cache"/*_pass
     else
-	refs="$(decide_refs "$@")"
-	commits="$(git rev-list --reverse $refs -- | tr "$NL" " ")"
+	refs=( $(decide_refs "$@") )
+	commits="$(git rev-list --reverse "${refs[@]}" -- | tr "$NL" " ")"
 	count="$(echo "$commits" | wc -w)"
 
 	if test 1 -gt "$count" ; then
@@ -467,17 +464,15 @@ or
     exit 5
 fi
 
-refs="$(decide_refs "$@")"
-refs="${refs% }"
-commits="$(git rev-list --reverse $refs -- | tr "$NL" " ")"
-count="$(echo "$commits" | wc -w)"
+refs=( $(decide_refs "$@") )
+commits=( $(git rev-list --reverse "${refs[@]}" -- | tr "$NL" " ") )
+count="$(echo "${commits[@]}" | wc -w)"
 
 if test 1 -gt "$count" ; then
     gettext 'List of commits to test is empty' 1>&2
     exit
 elif test -z "$GIT_QUIET" ; then
-    eval_gettext "\$refs will test \$count commits
-"
+    printf "$(eval_gettext "%s will test %d commits\n")" "${refs[*]}" "$count"
 fi
 
 trap "atexit_cleanup" INT TERM EXIT
@@ -486,6 +481,6 @@ lock
 
 make_output_dirs
 
-run_tests $commits
+run_tests "${commits[@]}"
 
 exit 1
diff --git a/test.sh b/test.sh
index 8f590d2..70d35fa 100644
--- a/test.sh
+++ b/test.sh
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 #
 # Copyright 2014-2015 Spotify AB. All rights reserved.
 #
@@ -15,7 +15,7 @@
 # the License.
 #
 export OPTIONS_SPEC="\
-sh $0 [options]
+bash $0 [options]
 
 Run tests
 
@@ -45,7 +45,7 @@ last=""
 pass=0
 fail=0
 
-shshell=${shshell:-/bin/sh}
+shshell=${shshell:-/bin/bash}
 
 total_argc=$#
 while [ $# != 0 ]
@@ -98,16 +98,16 @@ dot() {
 
     if [ $quit -gt 0 ] && ! [ -n "$1" ]; then
 	if [ $verb -lt 2 ]; then
-	    echo "\n$last"
+	    printf "\n%s\n" "$last"
 	fi
 	exit 5
     fi
 }
 
 info() {
-    last="$@"
+    last="$*"
     if [ $verb -ge 2 ]; then
-	echo "$@"
+	printf "%s\n" "$@"
     fi
 }