diff --git a/release/packages/generate-ucl.sh b/release/packages/generate-ucl.sh
--- a/release/packages/generate-ucl.sh
+++ b/release/packages/generate-ucl.sh
@@ -108,7 +108,7 @@
 
 	uclsource="${srctree}/release/packages/template.ucl"
 
-	if [ ! -z "${debug}" ]; then
+	if [ -n "${debug}" ]; then
 		echo ""
 		echo "==============================================================="
 		echo "DEBUG:"
@@ -128,11 +128,11 @@
 	fi
 
 	[ -z "${comment}" ] && comment="${outname} package"
-	[ ! -z "${_descr}" ] && comment="${comment} (${_descr})"
+	[ -n "${_descr}" ] && comment="${comment} (${_descr})"
 	[ -z "${desc}" ] && desc="${outname} package"
 
 	cp "${uclsource}" "${uclfile}"
-	if [ ! -z "${pkgdeps}" ]; then
+	if [ -n "${pkgdeps}" ]; then
 		echo 'deps: {' >> ${uclfile}
 		for dep in ${pkgdeps}; do
 			cat <<EOF >> ${uclfile}
diff --git a/release/release.sh b/release/release.sh
--- a/release/release.sh
+++ b/release/release.sh
@@ -62,7 +62,7 @@
 	# The default version control system command to obtain the sources.
 	for _dir in /usr/bin /usr/local/bin; do
 		[ -x "${_dir}/git" ] && VCSCMD="/${_dir}/git"
-		[ ! -z "${VCSCMD}" ] && break 2
+		[ -n "${VCSCMD}" ] && break 2
 	done
 
 	if [ -z "${VCSCMD}" -a -z "${NOGIT}" ]; then
@@ -182,7 +182,7 @@
 	fi
 
 	# Unset CHROOTBUILD_SKIP if the chroot(8) does not appear to exist.
-	if [ ! -z "${CHROOTBUILD_SKIP}" -a ! -e ${CHROOTDIR}/bin/sh ]; then
+	if [ -n "${CHROOTBUILD_SKIP}" -a ! -e ${CHROOTDIR}/bin/sh ]; then
 		CHROOTBUILD_SKIP=
 	fi
 
@@ -292,7 +292,7 @@
 		fi
 	fi
 
-	if [ ! -z "${EMBEDDEDPORTS}" ]; then
+	if [ -n "${EMBEDDEDPORTS}" ]; then
 		_OSVERSION=$(chroot ${CHROOTDIR} /usr/bin/uname -U)
 		REVISION=$(chroot ${CHROOTDIR} make -C /usr/src/release -V REVISION)
 		BRANCH=$(chroot ${CHROOTDIR} make -C /usr/src/release -V BRANCH)
@@ -317,7 +317,7 @@
 # chroot_build_target(): Build the userland and kernel for the build target.
 chroot_build_target() {
 	load_target_env
-	if [ ! -z "${EMBEDDEDBUILD}" ]; then
+	if [ -n "${EMBEDDEDBUILD}" ]; then
 		RELEASE_WMAKEFLAGS="${RELEASE_WMAKEFLAGS} \
 			TARGET=${EMBEDDED_TARGET} \
 			TARGET_ARCH=${EMBEDDED_TARGET_ARCH}"
@@ -327,7 +327,7 @@
 	fi
 	eval chroot ${CHROOTDIR} make -C /usr/src ${RELEASE_WMAKEFLAGS} buildworld
 	eval chroot ${CHROOTDIR} make -C /usr/src ${RELEASE_KMAKEFLAGS} buildkernel
-	if [ ! -z "${WITH_OCIIMAGES}" ]; then
+	if [ -n "${WITH_OCIIMAGES}" ]; then
 		eval chroot ${CHROOTDIR} make -C /usr/src ${RELEASE_WMAKEFLAGS} packages
 	fi
 
@@ -337,7 +337,7 @@
 # chroot_build_release(): Invoke the 'make release' target.
 chroot_build_release() {
 	load_target_env
-	if [ ! -z "${WITH_VMIMAGES}" ]; then
+	if [ -n "${WITH_VMIMAGES}" ]; then
 		if [ -z "${VMFORMATS}" ]; then
 			VMFORMATS="$(eval chroot ${CHROOTDIR} \
 				make -C /usr/src/release -V VMFORMATS)"
@@ -389,7 +389,7 @@
 		*)
 			;;
 	esac
-	[ ! -z "${RELEASECONF}" ] && . "${RELEASECONF}"
+	[ -n "${RELEASECONF}" ] && . "${RELEASECONF}"
 	export MAKE_FLAGS="${MAKE_FLAGS} TARGET=${EMBEDDED_TARGET}"
 	export MAKE_FLAGS="${MAKE_FLAGS} TARGET_ARCH=${EMBEDDED_TARGET_ARCH}"
 	export MAKE_FLAGS="${MAKE_FLAGS} ${CONF_FILES}"
@@ -439,7 +439,7 @@
 		esac
 	done
 	shift $(($OPTIND - 1))
-	if [ ! -z "${RELEASECONF}" ]; then
+	if [ -n "${RELEASECONF}" ]; then
 		if [ -e "${RELEASECONF}" ]; then
 			. ${RELEASECONF}
 		else
diff --git a/release/scripts/atlas-upload.sh b/release/scripts/atlas-upload.sh
--- a/release/scripts/atlas-upload.sh
+++ b/release/scripts/atlas-upload.sh
@@ -144,7 +144,7 @@
 		echo "Validating"
 		VALIDRESULT=$(/usr/local/bin/curl -s "${ATLAS_UPLOAD_URL}/api/v1/box/${USERNAME}/${BOX}/version/${VERSION}/provider/${PROVIDER}?access_token=${KEY}")
 		HOSTED_TOKEN=$(echo $VALIDRESULT | sed -e 's/.*"hosted"://' -e 's/,.*$//')
-		if [ ! -z ${TOKEN} -a "${HOSTED_TOKEN}" != "true" ]; then
+		if [ -n ${TOKEN} -a "${HOSTED_TOKEN}" != "true" ]; then
 			echo "Upload failed, try again."
 			exit 2
 		fi
diff --git a/release/scripts/mk-vmimage.sh b/release/scripts/mk-vmimage.sh
--- a/release/scripts/mk-vmimage.sh
+++ b/release/scripts/mk-vmimage.sh
@@ -91,7 +91,7 @@
 
 	. "${VMBUILDCONF}"
 
-	if [ ! -z "${VMCONFIG}" ] && [ ! -c "${VMCONFIG}" ]; then
+	if [ -n "${VMCONFIG}" ] && [ ! -c "${VMCONFIG}" ]; then
 		. "${VMCONFIG}"
 	fi
 
diff --git a/release/scripts/pkg-stage.sh b/release/scripts/pkg-stage.sh
--- a/release/scripts/pkg-stage.sh
+++ b/release/scripts/pkg-stage.sh
@@ -53,7 +53,7 @@
 export PKG_REPODIR="packages/${PKG_ABI}"
 
 /bin/mkdir -p ${ROOTDIR}/${PKG_REPODIR}
-if [ ! -z "${PKG_ALTABI}" ]; then
+if [ -n "${PKG_ALTABI}" ]; then
 	ln -s ${PKG_ABI} ${ROOTDIR}/packages/${PKG_ALTABI}
 fi
 
diff --git a/release/tools/arm.subr b/release/tools/arm.subr
--- a/release/tools/arm.subr
+++ b/release/tools/arm.subr
@@ -35,7 +35,7 @@
 		umount_loop ${DESTDIR}/dev 2>/dev/null
 	fi
 	umount_loop ${DESTDIR}
-	if [ ! -z "${mddev}" ]; then
+	if [ -n "${mddev}" ]; then
 		mdconfig -d -u ${mddev}
 	fi
 
diff --git a/release/tools/gce.conf b/release/tools/gce.conf
--- a/release/tools/gce.conf
+++ b/release/tools/gce.conf
@@ -124,7 +124,7 @@
 # Do everything except deleting resolv.conf since we construct our own
 # Googlized resolv.conf file in vm_extra_install_base.
 vm_emulation_cleanup() {
-	if ! [ -z "${QEMUSTATIC}" ]; then
+	if [ -n "${QEMUSTATIC}" ]; then
 		rm -f ${DESTDIR}/${EMULATOR}
 	fi
 	umount_loop ${DESTDIR}/dev
diff --git a/release/tools/vmimage.subr b/release/tools/vmimage.subr
--- a/release/tools/vmimage.subr
+++ b/release/tools/vmimage.subr
@@ -110,7 +110,7 @@
 	if [ -n "${WITHOUT_QEMU}" ]; then
 		return 0
 	fi
-	if ! [ -z "${QEMUSTATIC}" ]; then
+	if [ -n "${QEMUSTATIC}" ]; then
 		export EMULATOR=/qemu
 		cp ${QEMUSTATIC} ${DESTDIR}/${EMULATOR}
 	fi
@@ -133,7 +133,7 @@
 }
 
 vm_extra_enable_services() {
-	if [ ! -z "${VM_RC_LIST}" ]; then
+	if [ -n "${VM_RC_LIST}" ]; then
 		for _rcvar in ${VM_RC_LIST}; do
 			echo ${_rcvar}_enable="YES" >> ${DESTDIR}/etc/rc.conf
 		done