diff --git a/git-fixup b/git-fixup
index f0919e9..af66bb0 100755
--- a/git-fixup
+++ b/git-fixup
@@ -32,15 +32,15 @@ grok_diff='/^--- .*/p ;
 # Produce suggestion of commits by finding the sections of files with changes
 # staged (U1 to diff is used to give some context for when adding items to
 # lists etc) and looking up the previous commits touching those sections.
-function fixup_candidates_lines () {
+fixup_candidates_lines () {
     git diff --cached -U1 --no-prefix | sed -n "$grok_diff" | (
         file=''
         while read -r offs len ; do
-            if [ "$offs" = '---' ] ; then
+            if test "$offs" = '---'; then
                 file="$len"
             else
-                if [ "$len" != '0' ] ; then
-                    if [ "$file" != '/dev/null' ] ; then
+                if test "$len" != '0'; then
+                    if test "$file" != '/dev/null' ; then
                         git blame -sl -L "$offs,+$len" "$rev_range" -- "$file"
                     fi
                 fi
@@ -51,7 +51,7 @@ function fixup_candidates_lines () {
 
 # Produce suggestion of commits by taking the latest commit to each file with
 # staged changes
-function fixup_candidates_files () {
+fixup_candidates_files () {
     git diff --cached --name-only | (
         while read -r file; do
             git rev-list -n 1 -E --invert-grep --grep='^(fixup|squash)' "$rev_range" -- "$file"
@@ -60,12 +60,12 @@ function fixup_candidates_files () {
 }
 
 # Produce suggestion of all commits in $rev_range
-function fixup_candidates_all_commits () {
+fixup_candidates_all_commits () {
 	git rev-list "$rev_range" | sed 's/^/F /g'
 }
 
 # Pretty print details of a commit
-function print_sha () {
+print_sha () {
     local sha=$1
     local type=$2
 
@@ -73,11 +73,11 @@ function print_sha () {
 }
 
 # Call git commit
-function call_commit() {
+call_commit () {
     local flag=$op
     local target=$1
 
-    if [ "$op" = "amend" ] ; then
+    if test "$op" = "amend"; then
         flag=fixup
         target="amend:$target"
     fi
@@ -87,43 +87,43 @@ function call_commit() {
 }
 
 # Call git rebase
-function call_rebase() {
+call_rebase () {
     local target=$1
 
     # If our target-commit has a parent, we call a rebase with that
     # shellcheck disable=SC1083
-    if git rev-parse --quiet --verify "$target"~1^{commit} ; then
+    if git rev-parse --quiet --verify "$target"~1^{commit}; then
         git rebase --interactive --autosquash "$target~1"
     # If our target-commit exists but has no parents, it must be the very first commit
     # the repo. We simply call a rebase with --root
-    elif git rev-parse --quiet --verify "$target"^{commit} ; then
+    elif git rev-parse --quiet --verify "$target"^{commit}; then
         git rebase --interactive --autosquash --root
     fi
 }
 
 # Print list of fixup/squash candidates
-function print_candidates() {
+print_candidates () {
     (
-        if [ "$show_all" = "false" ] ; then
+        if [ "$show_all" = "false" ]; then
             fixup_candidates_lines
             fixup_candidates_files
         else
             fixup_candidates_all_commits
         fi
-    ) | sort -uk2 |  while read -r type sha; do
-        if [ -n "$sha" ] ; then
+    ) | sort -uk2 | while read -r type sha; do
+        if test -n "$sha"; then
             print_sha "$sha" "$type"
         fi
     done
 }
 
-function fallback_menu() {
+fallback_menu () {
     (
         IFS=$'\n'
         read -d '' -ra options
         PS3="Which commit should I $op? "
         select line in "${options[@]}"; do
-            if [ -z "$line" ] ; then
+            if test -z "$line"; then
                 declare -a args=("$REPLY")
                 case ${args[0]} in
                     quit|q)
@@ -132,7 +132,7 @@ function fallback_menu() {
                         ;;
                     show|s)
                         idx=$((args[1] - 1))
-                        if [ "$idx" -ge 0 ] ; then
+                        if test "$idx" -ge 0; then
                             git show "${options[$idx]%% *}" >&2
                         fi
                         ;;
@@ -157,7 +157,7 @@ function fallback_menu() {
 }
 
 show_menu () {
-    if [ -n "$fixup_menu" ] ; then
+    if test -n "$fixup_menu"; then
         eval command "$fixup_menu"
     else
         fallback_menu
@@ -173,7 +173,7 @@ create_commit=${GITFIXUPCOMMIT:-$(git config --default=false --type bool fixup.c
 base=${GITFIXUPBASE:-$(git config --default="" fixup.base)}
 show_all=false
 
-while [ $# -gt 0 ] ; do
+while test $# -gt 0; do
     case "$1" in
         -s|--squash)
             op="squash"
@@ -201,7 +201,7 @@ while [ $# -gt 0 ] ; do
             ;;
         -b|--base)
             shift
-            if [ $# -eq 0 ] ; then
+            if [ $# -eq 0 ]; then
                 die "--base requires an argument"
             fi
             base="$1"
@@ -218,58 +218,58 @@ while [ $# -gt 0 ] ; do
 done
 
 target="$1"
-if [ $# -gt 1 ] ; then
+if test $# -gt 1; then
     die "Pass only one ref, please"
 fi
 
-if [ -n "$target" ] ; then
+if test -n "$target"; then
     call_commit "$target"
-    if [ "$rebase" = "true" ] ; then
+    if test "$rebase" = "true"; then
         call_rebase "$target"
     fi
     exit
 fi
 
-if git diff --cached --quiet ; then
+if git diff --cached --quiet; then
     die 'No staged changes. Use git add -p to add them.'
 fi
 
 cd_to_toplevel
 
-if [ "$base" = "closest" ] ; then
+if test "$base" = "closest"; then
     base=$(git for-each-ref \
         --merged HEAD~1 \
         --sort=-committerdate \
-        refs/heads/ \
         --count 1 \
         --format='%(objectname)' \
+        refs/heads/ \
     )
-    if [ -z "$base" ] ; then
+    if test -z "$base"; then
         die "Could not find the ancestor branch"
     fi
 fi
 
-if [ -z "$base" ] ; then
+if test -z "$base"; then
     upstream=$(git rev-parse "@{upstream}" 2>/dev/null)
     head=$(git rev-parse HEAD 2>/dev/null)
-    if [ -n "$upstream" ] && [ "$upstream" != "$head" ] ; then
+    if test -n "$upstream" && test "$upstream" != "$head"; then
         base="$upstream"
     fi
 fi
 
-if [ -n "$base" ] ; then
+if test -n "$base"; then
     rev_range="$base..HEAD"
 else
     rev_range="HEAD"
 fi
 
-if [ "$create_commit" = "true" ] ; then
+if test "$create_commit" = "true"; then
     target=$(print_candidates | show_menu)
-    if [ -z "$target" ] ; then
+    if test -z "$target"; then
         exit
     fi
     call_commit "${target%% *}"
-    if [ "$rebase" = "true" ] ; then
+    if test "$rebase" = "true"; then
         call_rebase "${target%% *}"
     fi
 else