diff --git a/cmd/zed/zed.d/all-syslog.sh b/cmd/zed/zed.d/all-syslog.sh
index 270b1bc67e5c..b07cf0f295ad 100755
--- a/cmd/zed/zed.d/all-syslog.sh
+++ b/cmd/zed/zed.d/all-syslog.sh
@@ -1,50 +1,51 @@
 #!/bin/sh
 #
 # Copyright (C) 2013-2014 Lawrence Livermore National Security, LLC.
 # Copyright (c) 2020 by Delphix. All rights reserved.
 #
 
 #
 # Log the zevent via syslog.
 #
 
 [ -f "${ZED_ZEDLET_DIR}/zed.rc" ] && . "${ZED_ZEDLET_DIR}/zed.rc"
 . "${ZED_ZEDLET_DIR}/zed-functions.sh"
 
 zed_exit_if_ignoring_this_event
 
 # build a string of name=value pairs for this event
 msg="eid=${ZEVENT_EID} class=${ZEVENT_SUBCLASS}"
 
 if [ "${ZED_SYSLOG_DISPLAY_GUIDS}" = "1" ]; then
     [ -n "${ZEVENT_POOL_GUID}" ] && msg="${msg} pool_guid=${ZEVENT_POOL_GUID}"
     [ -n "${ZEVENT_VDEV_GUID}" ] && msg="${msg} vdev_guid=${ZEVENT_VDEV_GUID}"
 else
     [ -n "${ZEVENT_POOL}" ] && msg="${msg} pool='${ZEVENT_POOL}'"
     [ -n "${ZEVENT_VDEV_PATH}" ] && msg="${msg} vdev=$(basename "${ZEVENT_VDEV_PATH}")"
 fi
 
 # log pool state if state is anything other than 'ACTIVE'
 [ -n "${ZEVENT_POOL_STATE_STR}" ] && [ "$ZEVENT_POOL_STATE" -ne 0 ] && \
     msg="${msg} pool_state=${ZEVENT_POOL_STATE_STR}"
 
 # Log the following payload nvpairs if they are present
 [ -n "${ZEVENT_VDEV_STATE_STR}" ]  && msg="${msg} vdev_state=${ZEVENT_VDEV_STATE_STR}"
 [ -n "${ZEVENT_CKSUM_ALGORITHM}" ] && msg="${msg} algorithm=${ZEVENT_CKSUM_ALGORITHM}"
 [ -n "${ZEVENT_ZIO_SIZE}" ]        && msg="${msg} size=${ZEVENT_ZIO_SIZE}"
 [ -n "${ZEVENT_ZIO_OFFSET}" ]      && msg="${msg} offset=${ZEVENT_ZIO_OFFSET}"
 [ -n "${ZEVENT_ZIO_PRIORITY}" ]    && msg="${msg} priority=${ZEVENT_ZIO_PRIORITY}"
 [ -n "${ZEVENT_ZIO_ERR}" ]         && msg="${msg} err=${ZEVENT_ZIO_ERR}"
 [ -n "${ZEVENT_ZIO_FLAGS}" ]       && msg="${msg} flags=$(printf '0x%x' "${ZEVENT_ZIO_FLAGS}")"
 
 # log delays that are >= 10 milisec
 [ -n "${ZEVENT_ZIO_DELAY}" ] && [ "$ZEVENT_ZIO_DELAY" -gt 10000000 ] && \
     msg="${msg} delay=$((ZEVENT_ZIO_DELAY / 1000000))ms"
 
 # list the bookmark data together
+# shellcheck disable=SC2153
 [ -n "${ZEVENT_ZIO_OBJSET}" ] && \
     msg="${msg} bookmark=${ZEVENT_ZIO_OBJSET}:${ZEVENT_ZIO_OBJECT}:${ZEVENT_ZIO_LEVEL}:${ZEVENT_ZIO_BLKID}"
 
 zed_log_msg "${msg}"
 
 exit 0
diff --git a/scripts/make_gitrev.sh b/scripts/make_gitrev.sh
index da21455332ab..e7f4ce8844d5 100755
--- a/scripts/make_gitrev.sh
+++ b/scripts/make_gitrev.sh
@@ -1,78 +1,78 @@
 #!/bin/sh
 
 #
 # CDDL HEADER START
 #
 # This file and its contents are supplied under the terms of the
 # Common Development and Distribution License ("CDDL"), version 1.0.
 # You may only use this file in accordance with the terms of version
 # 1.0 of the CDDL.
 #
 # A full copy of the text of the CDDL should have accompanied this
 # source.  A copy of the CDDL is also available via the Internet at
 # http://www.illumos.org/license/CDDL.
 #
 # CDDL HEADER END
 #
 
 # Copyright (c) 2018 by Delphix. All rights reserved.
 # Copyright (c) 2018 by Matthew Thode. All rights reserved.
 
 #
 # Generate zfs_gitrev.h.  Note that we need to do this for every
 # invocation of `make`, including for incremental builds.  Therefore we
 # can't use a zfs_gitrev.h.in file which would be processed only when
 # `configure` is run.
 #
 
 set -e -u
 
 dist=no
 distdir=.
 while getopts D: flag
 do
 	case $flag in
 		\?) echo "Usage: $0 [-D distdir] [file]" >&2; exit 1;;
 		D)  dist=yes; distdir=${OPTARG};;
 	esac
 done
 shift $((OPTIND - 1))
 
 top_srcdir="$(dirname "$0")/.."
 GITREV="${1:-include/zfs_gitrev.h}"
 
 # GITREV should be a relative path (relative to top_builddir or distdir)
 case "${GITREV}" in
 	/*) echo "Error: ${GITREV} should be a relative path" >&2
 	    exit 1;;
 esac
 
 ZFS_GITREV=$({ cd "${top_srcdir}" &&
 	git describe --always --long --dirty 2>/dev/null; } || :)
 
-if [ "x${ZFS_GITREV}" = x ]
+if [ -z "${ZFS_GITREV}" ]
 then
 	# If the source directory is not a git repository, check if the file
 	# already exists (in the source)
 	if [ -f "${top_srcdir}/${GITREV}" ]
 	then
 		ZFS_GITREV=$(sed -n \
 			'1s/^#define[[:blank:]]ZFS_META_GITREV "\([^"]*\)"$/\1/p' \
 			"${top_srcdir}/${GITREV}")
 	fi
 elif [ ${dist} = yes ]
 then
 	# Append -dist when creating distributed sources from a git repository
 	ZFS_GITREV="${ZFS_GITREV}-dist"
 fi
 ZFS_GITREV=${ZFS_GITREV:-unknown}
 
 GITREVTMP="${GITREV}~"
 printf '#define\tZFS_META_GITREV "%s"\n' "${ZFS_GITREV}" >"${GITREVTMP}"
 GITREV="${distdir}/${GITREV}"
 if cmp -s "${GITREV}" "${GITREVTMP}"
 then
 	rm -f "${GITREVTMP}"
 else
 	mv -f "${GITREVTMP}" "${GITREV}"
 fi
diff --git a/scripts/man-dates.sh b/scripts/man-dates.sh
index 186d94639a56..39f1b5fb1324 100755
--- a/scripts/man-dates.sh
+++ b/scripts/man-dates.sh
@@ -1,12 +1,12 @@
 #!/bin/sh
 
 # This script updates the date lines in the man pages to the date of the last
 # commit to that file.
 
 set -eu
 
 find man -type f | while read -r i ; do
     git_date=$(git log -1 --date=short --format="%ad" -- "$i")
-    [ "x$git_date" = "x" ] && continue
+    [ -z "$git_date" ] && continue
     sed -i "s|^\.Dd.*|.Dd $(date -d "$git_date" "+%B %-d, %Y")|" "$i"
 done