diff --git a/forgejo-release.sh b/forgejo-release.sh
index 01001a2..12c34e9 100755
--- a/forgejo-release.sh
+++ b/forgejo-release.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env sh
 # SPDX-License-Identifier: MIT
 
 set -e
@@ -27,9 +27,7 @@ TAG_URL=$(echo "$TAG" | sed 's/\//%2F/g')
 export GNUPGHOME
 
 get_arch() {
-    local arch
-    arch="$(uname -m)"
-
+    arch=$(uname -m)
     case "$arch" in
         x86_64)   arch="amd64" ;;
         i386|i686) arch="i386" ;;
@@ -47,28 +45,28 @@ get_arch() {
 setup_tea() {
     if command -v tea >/dev/null 2>&1; then
         TEA_BIN=$(command -v tea)
-    elif ! test -f $TEA_BIN; then
+    elif ! [ -f "$TEA_BIN" ]; then
         ARCH=$(get_arch)
-        curl -sL https://dl.gitea.io/tea/$TEA_VERSION/tea-$TEA_VERSION-linux-"$ARCH" >$TEA_BIN
-        chmod +x $TEA_BIN
+        curl -sL "https://dl.gitea.io/tea/$TEA_VERSION/tea-$TEA_VERSION-linux-$ARCH" >"$TEA_BIN"
+        chmod +x "$TEA_BIN"
     fi
 }
 
 get_tag() {
-    if ! test -f "$TAG_FILE"; then
+    if ! [ -f "$TAG_FILE" ]; then
         if api GET repos/$REPO/tags/"$TAG_URL" >"$TAG_FILE"; then
             echo "tag $TAG exists"
         else
             echo "tag $TAG does not exists"
         fi
     fi
-    test -s "$TAG_FILE"
+    [ -s "$TAG_FILE" ]
 }
 
 matched_tag() {
     if get_tag; then
-        local sha=$(jq --raw-output .commit.sha <"$TAG_FILE")
-        test "$sha" = "$SHA"
+        sha=$(jq --raw-output .commit.sha <"$TAG_FILE")
+        [ "$sha" = "$SHA" ]
     else
         return 1
     fi
@@ -101,22 +99,23 @@ upload_release() {
     # assets is defined as a list of arguments, where values may contain whitespace and need to be quoted like this -a "my file.txt" -a "file.txt".
     # It is expanded using "${assets[@]}" which preserves the separation of arguments and not split whitespace containing values.
     # For reference, see https://github.com/koalaman/shellcheck/wiki/SC2086#exceptions
-    local assets=()
+    set --
     for file in "$RELEASE_DIR"/*; do
-        assets=("${assets[@]}" -a "$file")
+        set -- "$@" -a "$file"
     done
-    if $PRERELEASE || echo "${TAG}" | grep -qi '\-rc'; then
+    releaseType=""
+    if ${PRERELEASE:-false} || echo "$TAG" | grep -qi -- '-rc'; then
         releaseType="--prerelease"
         echo "Uploading as Pre-Release"
     else
         echo "Uploading as Stable"
     fi
     ensure_tag
-    if ! $TEA_BIN release create "${assets[@]}" --repo $REPO --note "$RELEASENOTES" --tag "$TAG" --title "$TITLE" --draft ${releaseType} >&"$TMP_DIR"/tea.log; then
-        if grep --quiet 'Unknown API Error: 500' "$TMP_DIR"/tea.log && grep --quiet services/release/release.go:194 "$TMP_DIR"/tea.log; then
+    if ! "$TEA_BIN" release create "$@" --repo "$REPO" --note "$RELEASENOTES" --tag "$TAG" --title "$TITLE" --draft ${releaseType} >"$TMP_DIR"/tea.log 2>&1; then
+        if grep --quiet 'Unknown API Error: 500' "$TMP_DIR"/tea.log && grep --quiet 'services/release/release.go:194' "$TMP_DIR"/tea.log; then
             echo "workaround v1.20 race condition https://codeberg.org/forgejo/forgejo/issues/1370"
             sleep 10
-            $TEA_BIN release create "${assets[@]}" --repo $REPO --note "$RELEASENOTES" --tag "$TAG" --title "$TITLE" --draft ${releaseType}
+            "$TEA_BIN" release create "$@" --repo "$REPO" --note "$RELEASENOTES" --tag "$TAG" --title "$TITLE" --draft ${releaseType}
         else
             cat "$TMP_DIR"/tea.log
             return 1
@@ -127,47 +126,45 @@ upload_release() {
 }
 
 release_draft() {
-    local state="$1"
-
-    local id=$(api GET repos/$REPO/releases/tags/"$TAG_URL" | jq --raw-output .id)
-
-    api PATCH repos/$REPO/releases/"$id" --data-raw '{"draft": '"$state"', "hide_archive_links": '$HIDE_ARCHIVE_LINK'}'
+    state="$1"
+    rid=$(api GET repos/$REPO/releases/tags/"$TAG_URL" | jq --raw-output .id)
+    api PATCH repos/$REPO/releases/"$rid" --data-raw '{"draft": '"$state"', "hide_archive_links": '"$HIDE_ARCHIVE_LINK"'}'
 }
 
 maybe_use_release_note_assistant() {
-    if "$RELEASE_NOTES_ASSISTANT"; then
-        curl --fail -s -S -o rna https://code.forgejo.org/forgejo/release-notes-assistant/releases/download/$RELEASE_NOTES_ASSISTANT_VERSION/release-notes-assistant
+    if ${RELEASE_NOTES_ASSISTANT:-false}; then
+        curl --fail -s -S -o rna "https://code.forgejo.org/forgejo/release-notes-assistant/releases/download/$RELEASE_NOTES_ASSISTANT_VERSION/release-notes-assistant"
         chmod +x ./rna
-        mkdir -p $RELEASE_NOTES_ASSISTANT_WORKDIR
-        ./rna --workdir=$RELEASE_NOTES_ASSISTANT_WORKDIR --storage release --storage-location "$TAG" --token "$TOKEN" --forgejo-url "$SCHEME://$HOST" --repository $REPO --token "$TOKEN" release "$TAG"
+        mkdir -p "$RELEASE_NOTES_ASSISTANT_WORKDIR"
+        ./rna --workdir="$RELEASE_NOTES_ASSISTANT_WORKDIR" --storage release --storage-location "$TAG" --token "$TOKEN" --forgejo-url "$SCHEME://$HOST" --repository "$REPO" --token "$TOKEN" release "$TAG"
     fi
 }
 
 sign_release() {
-    local passphrase
-    if test -s "$GPG_PASSPHRASE"; then
+    passphrase=""
+    if [ -s "$GPG_PASSPHRASE" ]; then
         passphrase="--passphrase-file $GPG_PASSPHRASE"
     fi
     gpg --import --no-tty --pinentry-mode loopback $passphrase "$GPG_PRIVATE_KEY"
     for asset in "$RELEASE_DIR"/*; do
-        if [[ $asset =~ .sha256$ ]]; then
-            continue
-        fi
+        case "$asset" in
+            *.sha256) continue ;;
+        esac
         gpg --armor --detach-sign --no-tty --pinentry-mode loopback $passphrase <"$asset" >"$asset".asc
     done
 }
 
 maybe_sign_release() {
-    if test -s "$GPG_PRIVATE_KEY"; then
+    if [ -s "$GPG_PRIVATE_KEY" ]; then
         sign_release
     fi
 }
 
 maybe_override() {
-    if test "$OVERRIDE" = "false"; then
+    if [ "$OVERRIDE" = "false" ]; then
         return
     fi
-    api DELETE repos/$REPO/releases/tags/"$TAG_URL" >&/dev/null || true
+    api DELETE repos/$REPO/releases/tags/"$TAG_URL" >/dev/null 2>&1 || true
     if get_tag && ! matched_tag; then
         delete_tag
     fi
@@ -176,8 +173,8 @@ maybe_override() {
 upload() {
     setup_api
     setup_tea
-    rm -f ~/.config/tea/config.yml
-    GITEA_SERVER_TOKEN=$TOKEN $TEA_BIN login add --url $FORGEJO
+    rm -f "$HOME/.config/tea/config.yml"
+    GITEA_SERVER_TOKEN=$TOKEN "$TEA_BIN" login add --url "$FORGEJO"
     maybe_sign_release
     maybe_override
     upload_release
@@ -207,14 +204,15 @@ api() {
     path=$1
     shift
 
-    curl --fail -X "$method" -sS -H "Content-Type: application/json" -H "Authorization: token $TOKEN" "$@" $FORGEJO/api/v1/"$path"
+    curl --fail -X "$method" -sS -H "Content-Type: application/json" -H "Authorization: token $TOKEN" "$@" "$FORGEJO/api/v1/$path"
 }
 
 wait_release() {
-    local ready=false
-    for i in $(seq $RETRY); do
+    ready=false
+    i=1
+    while [ "$i" -le "$RETRY" ]; do
         if api GET repos/$REPO/releases/tags/"$TAG_URL" | jq --raw-output .draft >"$TMP_DIR"/draft; then
-            if test "$(cat "$TMP_DIR"/draft)" = "false"; then
+            if [ "$(cat "$TMP_DIR"/draft)" = "false" ]; then
                 ready=true
                 break
             fi
@@ -223,9 +221,10 @@ wait_release() {
             echo "release $TAG does not exist yet"
         fi
         echo "waiting $DELAY seconds"
-        sleep $DELAY
+        sleep "$DELAY"
+        i=$((i+1))
     done
-    if ! $ready; then
+    if [ "$ready" != "true" ]; then
         echo "no release for $TAG"
         return 1
     fi
@@ -234,17 +233,17 @@ wait_release() {
 download() {
     setup_api
     (
-        mkdir -p $RELEASE_DIR
-        cd $RELEASE_DIR
-        if [[ ${DOWNLOAD_LATEST} == "true" ]]; then
+        mkdir -p "$RELEASE_DIR"
+        cd "$RELEASE_DIR" || exit 1
+        if [ "${DOWNLOAD_LATEST}" = "true" ]; then
             echo "Downloading the latest release"
             api GET repos/$REPO/releases/latest >"$TMP_DIR"/assets.json
-        elif [[ ${DOWNLOAD_LATEST} == "false" ]]; then
+        elif [ "${DOWNLOAD_LATEST}" = "false" ]; then
             wait_release
             echo "Downloading tagged release ${TAG}"
             api GET repos/$REPO/releases/tags/"$TAG_URL" >"$TMP_DIR"/assets.json
         fi
-        jq --raw-output '.assets[] | "\(.browser_download_url) \(.name)"' <"$TMP_DIR"/assets.json | while read url name; do # `name` may contain whitespace, therefore, it must be last
+        jq --raw-output '.assets[] | "\(.browser_download_url) \(.name)"' <"$TMP_DIR"/assets.json | while read url name; do
             url=$(echo "$url" | sed "s#/download/${TAG}/#/download/${TAG_URL}/#")
             curl --fail -H "Authorization: token $TOKEN" -o "$name" -L "$url"
         done
@@ -252,8 +251,12 @@ download() {
 }
 
 missing() {
-    echo need upload or download argument got nothing
+    echo "need upload or download argument got nothing"
     exit 1
 }
 
-${@:-missing}
+if [ "$#" -gt 0 ]; then
+    "$@"
+else
+    missing
+fi
diff --git a/testdata/forgejo-release-test.sh b/testdata/forgejo-release-test.sh
index 7fe332b..ebd63de 100755
--- a/testdata/forgejo-release-test.sh
+++ b/testdata/forgejo-release-test.sh
@@ -1,21 +1,22 @@
-#!/bin/bash
+#!/usr/bin/env sh
 # SPDX-License-Identifier: MIT
 
 set -ex
-PS4='${BASH_SOURCE[0]}:$LINENO: ${FUNCNAME[0]}:  '
+PS4='${0##*/}:$LINENO: '
 
 test_system_tea_bin() {
-	SYSTEM_TEA_BIN=$TMP_DIR/tea
-	touch $SYSTEM_TEA_BIN && chmod +x $SYSTEM_TEA_BIN
-	export PATH=$TMP_DIR:$PATH
+    SYSTEM_TEA_BIN=$TMP_DIR/tea
+    : >"$SYSTEM_TEA_BIN" && chmod +x "$SYSTEM_TEA_BIN"
+    PATH=$TMP_DIR:$PATH
+    export PATH
     setup_tea
-	test $TEA_BIN == $SYSTEM_TEA_BIN
+    [ "$TEA_BIN" = "$SYSTEM_TEA_BIN" ]
 }
 
 test_download_tea_bin() {
     # assume tea is not installed on system
     setup_tea
-    test $TEA_BIN == $TMP_DIR/tea
+    [ "$TEA_BIN" = "$TMP_DIR/tea" ]
 }
 
 test_teardown() {
@@ -24,23 +25,23 @@ test_teardown() {
     api DELETE repos/$REPO/tags/$TAG || true
     rm -fr dist/release
     setup_tea
-    $TEA_BIN login delete $DOER || true
+    "$TEA_BIN" login delete "$DOER" || true
 }
 
 test_reset_repo() {
-    local project="$1"
+    project="$1"
     api DELETE repos/$REPO || true
     api POST user/repos --data-raw '{"name":"'$project'", "auto_init":true}'
-    git clone $FORGEJO/$REPO $TMP_DIR/repo
-    SHA=$(git -C $TMP_DIR/repo rev-parse HEAD)
+    git clone "$FORGEJO/$REPO" "$TMP_DIR/repo"
+    SHA=$(git -C "$TMP_DIR/repo" rev-parse HEAD)
 }
 
 test_setup() {
-    local project="$1"
-    test_reset_repo $project
-    mkdir -p $RELEASE_DIR
-    touch $RELEASE_DIR/file-one.txt
-    touch $RELEASE_DIR/file-two.txt
+    project="$1"
+    test_reset_repo "$project"
+    mkdir -p "$RELEASE_DIR"
+    : >"$RELEASE_DIR/file-one.txt"
+    : >"$RELEASE_DIR/file-two.txt"
 }
 
 test_wait_release_fail() {
@@ -69,12 +70,12 @@ test_ensure_tag() {
     # idempotent
     #
     ensure_tag
-    mv $TAG_FILE $TMP_DIR/tag1.json
+    mv "$TAG_FILE" "$TMP_DIR/tag1.json"
 
     ensure_tag
-    mv $TAG_FILE $TMP_DIR/tag2.json
+    mv "$TAG_FILE" "$TMP_DIR/tag2.json"
 
-    diff -u $TMP_DIR/tag[12].json
+    diff -u "$TMP_DIR/tag1.json" "$TMP_DIR/tag2.json"
     #
     # sanity check on the SHA of an existing tag
     #
@@ -92,7 +93,7 @@ test_maybe_sign_release_no_gpg() {
     GPG_PRIVATE_KEY=
     maybe_sign_release
 
-    ! test -f $RELEASE_DIR/file-one.txt.asc
+    ! [ -f "$RELEASE_DIR/file-one.txt.asc" ]
 }
 
 test_maybe_sign_release_gpg_no_passphrase() {
@@ -117,28 +118,28 @@ test_maybe_sign_release_gpg() {
 }
 
 test_maybe_sign_release_skipped() {
-    ! test -f $RELEASE_DIR/file-one.txt.sha256.asc
-    ! test -f $RELEASE_DIR/file-two.txt.sha256.asc
+    ! [ -f "$RELEASE_DIR/file-one.txt.sha256.asc" ]
+    ! [ -f "$RELEASE_DIR/file-two.txt.sha256.asc" ]
 }
 
 test_maybe_sign_release_verify() {
-    for file in $RELEASE_DIR/file-one.txt $RELEASE_DIR/file-two.txt; do
-        gpg --verify $file.asc $file
+    for file in "$RELEASE_DIR/file-one.txt" "$RELEASE_DIR/file-two.txt"; do
+        gpg --verify "$file.asc" "$file"
     done
 }
 
 test_maybe_sign_release_setup() {
-    local name="$1"
+    name="$1"
 
     echo "========= maybe_sign_release $name ========="
-    RELEASE_DIR=$TMP_DIR/$name
-    mkdir -p $RELEASE_DIR
-    GNUPGHOME=$TMP_DIR/$name/.gnupg
-    mkdir -p $GNUPGHOME
-    touch $RELEASE_DIR/file-one.txt
-    touch $RELEASE_DIR/file-one.txt.sha256
-    touch $RELEASE_DIR/file-two.txt
-    touch $RELEASE_DIR/file-two.txt.sha256
+    RELEASE_DIR="$TMP_DIR/$name"
+    mkdir -p "$RELEASE_DIR"
+    GNUPGHOME="$TMP_DIR/$name/.gnupg"
+    mkdir -p "$GNUPGHOME"
+    : >"$RELEASE_DIR/file-one.txt"
+    : >"$RELEASE_DIR/file-one.txt.sha256"
+    : >"$RELEASE_DIR/file-two.txt"
+    : >"$RELEASE_DIR/file-two.txt.sha256"
 }
 
 test_maybe_sign_release() {
@@ -148,31 +149,31 @@ test_maybe_sign_release() {
 }
 
 test_run() {
-    local user="$1"
-    local project="$2"
+    user="$1"
+    project="$2"
     test_teardown
-    to_push=$TMP_DIR/binaries-releases-to-push
-    pulled=$TMP_DIR/binaries-releases-pulled
-    RELEASE_DIR=$to_push
-    REPO=$user/$project
-    test_setup $project
+    to_push="$TMP_DIR/binaries-releases-to-push"
+    pulled="$TMP_DIR/binaries-releases-pulled"
+    RELEASE_DIR="$to_push"
+    REPO="$user/$project"
+    test_setup "$project"
     test_ensure_tag
     test_create_delete_tag
     DELAY=0
     test_wait_release_fail
     echo "================================ TEST BEGIN"
     upload
-    RELEASE_DIR=$pulled
+    RELEASE_DIR="$pulled"
     download
-    diff -r $to_push $pulled
+    diff -r "$to_push" "$pulled"
     echo "================================ TEST END"
     test_wait_release
 }
 
 TMP_DIR=$(mktemp -d)
 
-trap "rm -fr $TMP_DIR" EXIT
+trap 'rm -fr "$TMP_DIR"' 0 INT TERM
 
 : ${TAG:=v17.8.20-1}
 
-. $(dirname $0)/../forgejo-release.sh
+. "$(dirname "$0")/../forgejo-release.sh"