diff --git a/scripts/tools/release.sh b/scripts/tools/release.sh
index 5361db2c..14da1144 100755
--- a/scripts/tools/release.sh
+++ b/scripts/tools/release.sh
@@ -6,7 +6,9 @@
 #
 # SPDX-License-Identifier: LGPL-3.0-or-later
 
-setopt ERR_EXIT #exit on error
+set -e
+set -u
+
 #Project name
 project=volk
 #What to prefix in release tags in front of the version number
@@ -55,22 +57,22 @@ shortlog="
 
 ## [${version}] - $(date +'%Y-%m-%d')
 
-$(git shortlog -e ${last_release}..HEAD)
+$(git shortlog -e "${last_release}"..HEAD)
 "
 echo "${shortlog}"
 
-echo "${shortlog}" > ${deltafile}
+echo "${shortlog}" > "${deltafile}"
 
-${EDITOR} ${deltafile}
+${EDITOR} "${deltafile}"
 
-echo "$(cat ${deltafile})" >> ${changelog}
-echo "${releaseprefix}${version}" > ${lastreleasefile}
+cat "${deltafile}" >> "${changelog}"
+echo "${releaseprefix}${version}" > "${lastreleasefile}"
 
 # 3. Commit changelog
 git commit -m "Release ${version}" "${changelog}" "${lastreleasefile}" CMakeLists.txt
 
 # 4. prepare tag
-cat "${deltafile}" > ${annotationfile}
+cat "${deltafile}" > "${annotationfile}"
 # Append the HEAD commit hash to the annotation
 echo "git-describes-hash: $(git rev-parse --verify HEAD)" >> "${annotationfile}"
 
@@ -93,11 +95,11 @@ outfile="${tempdir}/${tarprefix}.tar"
 git archive "--output=${outfile}" "--prefix=${tarprefix}/" HEAD
 # Append submodule archives
 git submodule foreach --recursive "git archive --output ${tempdir}/${tarprefix}-sub-\${sha1}.tar --prefix=${tarprefix}/\${sm_path}/ HEAD"
-if [[ $(ls ${tempdir}/${tarprefix}-sub*.tar | wc -l) != 0  ]]; then
+if [[ $(ls "${tempdir}/${tarprefix}"-sub*.tar | wc -l) != 0  ]]; then
   # combine all archives into one tar
-  tar --concatenate --file ${outfile} ${tempdir}/${tarprefix}-sub*.tar
+  tar --concatenate --file "${outfile}" "${tempdir}/${tarprefix}"-sub*.tar
 fi
-echo "Created tape archive '${outfile}' of size $(du -h ${outfile})."
+echo "Created tape archive ${outfile} of size $(du -h "${outfile}")."
 
 # 6. compress
 echo  "compressing:"
@@ -113,15 +115,17 @@ echo "…compressed."
 # 7. sign
 
 # 7.1 with openbsd-signify
-echo "signing file list…"
-filelist="${tempdir}/${version}.sha256"
-pushd "${tempdir}"
-sha256sum --tag *.tar.* > "${filelist}"
-signify-openbsd -S -e -s "${seckey}" -m "${filelist}"
-echo "…signed. Check with 'signify -C -p \"${pubkey}\" -x \"${filelist}\"'."
-signify-openbsd -C -p "${pubkey}" -x "${filelist}.sig"
-popd
-echo "checked."
+if type 'signify-openbsd' > /dev/null; then
+  echo "signing file list…"
+  filelist="${tempdir}/${version}.sha256"
+  pushd "${tempdir}" || exit 1
+  sha256sum --tag -- *.tar.* > "${filelist}"
+  signify-openbsd -S -e -s "${seckey}" -m "${filelist}"
+  echo "…signed. Check with 'signify -C -p \"${pubkey}\" -x \"${filelist}\"'."
+  signify-openbsd -C -p "${pubkey}" -x "${filelist}.sig"
+  popd
+  echo "checked."
+fi
 
 # 7.2 with GPG
 echo "signing tarballs with GPG ..."
@@ -143,4 +147,3 @@ echo "Release tag: 'git push ${remote} v${releaseprefix}${version}'"
 #    git push "${remote}" HEAD
 #    git push "${remote}" "v${releaseprefix}${version}"
 #fi
-