diff --git a/bin/profile_axis b/bin/profile_axis
index 35a7fa2acf4..9ec5850243a 100755
--- a/bin/profile_axis
+++ b/bin/profile_axis
@@ -1,4 +1,4 @@
 #!/bin/bash
-SCRIPT_LOCATION=$(dirname $(readlink -f $0))
-python3 -mcProfile -o axis.profile $SCRIPT_LOCATION/axis "$@"
+SCRIPT_LOCATION=$(dirname "$(readlink -f "$0")")
+python3 -mcProfile -o axis.profile "$SCRIPT_LOCATION"/axis "$@"
 (echo sort cumulative; echo stats 20) | python3 -mpstats axis.profile
diff --git a/debian/configure b/debian/configure
index 8315085c923..bf13b05a15f 100755
--- a/debian/configure
+++ b/debian/configure
@@ -28,7 +28,7 @@ EOF
 
 cd "${0%/*}"
 
-if [ "$1" == "-h" -o "$1" == "-help" -o "$1" == "--help" ]; then
+if [ "$1" == "-h" ] || [ "$1" == "-help" ] || [ "$1" == "--help" ]; then
     usage
     exit 0
 fi
@@ -168,7 +168,7 @@ sed \
     -e "s|@YAPPS_RUNTIME@|$YAPPS_RUNTIME|g" \
     -e "s#@ENABLE_BUILD_DOCUMENTATION@#$ENABLE_BUILD_DOCUMENTATION#g" \
     -e '/^\s*,\s*$/d' \
-    $*
+    "$@"
 }
 
 if [[ -z "${COMPAT}" ]]; then
diff --git a/debian/tests/linuxcnc-test b/debian/tests/linuxcnc-test
index 903b670d5c2..807c0a9c173 100755
--- a/debian/tests/linuxcnc-test
+++ b/debian/tests/linuxcnc-test
@@ -4,7 +4,7 @@
 
 set -e
 
-cd $(dirname $0)
+cd "$(dirname "$0")"
 
 if ! linuxcnc -r linuxcnc-test.ini ; then
     echo "error: failed to execute linuxcnc"
diff --git a/debian/tests/rs274-test b/debian/tests/rs274-test
index c555b93c81d..9f97d962d12 100755
--- a/debian/tests/rs274-test
+++ b/debian/tests/rs274-test
@@ -2,17 +2,17 @@
 
 set -e
 
-cd $(dirname $0)
+cd "$(dirname "$0")"
 
 log=$AUTOPKGTEST_TMP/rs274.out
 
-if ! rs274 -g rs274.ngc > $log 2>&1 ; then
+if ! rs274 -g rs274.ngc > "$log" 2>&1 ; then
     echo "error: failed to run rs274"
-    cat $log
+    cat "$log"
     exit 1
 fi
 
-if ! diff -u $log rs274.res ; then
+if ! diff -u "$log" rs274.res ; then
     echo "error: rs274 output do not match rs274.res"
     exit 1
 fi
diff --git a/nc_files/M101 b/nc_files/M101
index eed466e6429..9d2eb115f18 100755
--- a/nc_files/M101
+++ b/nc_files/M101
@@ -8,8 +8,8 @@
 P=$1
 Q=$2
 
-MCMD=$(readlink -nf $0) ;# canonical file name
-MNAME=$(basename $MCMD)
+MCMD=$(readlink -nf "$0")
+MNAME=$(basename "$MCMD")
 
 echo
 echo "Example for User M-code invocation:"
@@ -19,4 +19,4 @@ echo "$MNAME P$P Q$Q"
 
 # if a M1nn command exits with nonzero status,
 # the G-code program exits.  So always exit 0.
-exit 0 ;# 0 for success
+exit 0
diff --git a/scripts/get-deb-component-from-git b/scripts/get-deb-component-from-git
index 7c0cf3f9b1f..8b28f72406d 100755
--- a/scripts/get-deb-component-from-git
+++ b/scripts/get-deb-component-from-git
@@ -1,12 +1,12 @@
 #!/bin/bash
 
-if [ ! -z "$EMC2_HOME" ]; then
-    source $EMC2_HOME/scripts/githelper.sh
+if [ -n "$EMC2_HOME" ]; then
+    source "$EMC2_HOME"/scripts/githelper.sh
 else
-    source $(git rev-parse --show-toplevel)/scripts/githelper.sh
+    source "$(git rev-parse --show-toplevel)"/scripts/githelper.sh
 fi
 
-githelper $1
+githelper "$1"
 
-echo $DEB_COMPONENT
+echo "$DEB_COMPONENT"
 
diff --git a/scripts/get-version-from-git b/scripts/get-version-from-git
index 544181b3fa2..3c77834f959 100755
--- a/scripts/get-version-from-git
+++ b/scripts/get-version-from-git
@@ -1,18 +1,18 @@
 #!/bin/bash
 
-if [ ! -z "$EMC2_HOME" ]; then
-    source $EMC2_HOME/scripts/githelper.sh
+if [ -n "$EMC2_HOME" ]; then
+    source "$EMC2_HOME"/scripts/githelper.sh
 else
-    source $(git rev-parse --show-toplevel)/scripts/githelper.sh
+    source "$(git rev-parse --show-toplevel)"/scripts/githelper.sh
 fi
 
-githelper $1
+githelper "$1"
 
 if [ "$DEB_COMPONENT" = "scratch" ]; then
     # unknown branches get the VERSION file, plus the branch name (with any
     # characters that are invalid in debian version numbers replaced with
     # dashes '-'), plus the HEAD commit SHA1
-    echo v$(git show HEAD:VERSION | cut -d ' ' -f 1)~${GIT_BRANCH//[^-.+:~a-z0-9]/-}~$(git show --pretty=format:%h HEAD | head -1)
+    echo "v$(git show HEAD:VERSION | cut -d ' ' -f 1)~${GIT_BRANCH//[^-.+:~a-z0-9]/-}~$(git show --pretty=format:%h HEAD | head -1)"
 else
     # known branches get the "describe" of the most recent signed git tag,
     # or of the most recent unsigned tag if no signed tags are found
diff --git a/scripts/githelper.sh b/scripts/githelper.sh
index 283192d2f13..90be8fb7139 100644
--- a/scripts/githelper.sh
+++ b/scripts/githelper.sh
@@ -12,6 +12,7 @@
 # Sets GIT_TAG to the most recent signed tag (this will fall back to the
 # most recent tag of any kind if no signed tag is found).
 #
+# shellcheck shell=bash
 
 
 function githelper() {
@@ -45,32 +46,35 @@ function githelper() {
             ;;
         *)
             GIT_TAG_GLOB="*"
+            # Disable unused variable warnings on DEB_COMPONENT
+            # shellcheck disable=SC2034
             DEB_COMPONENT="scratch"
             ;;
     esac
 
 
     # use the gnupg keyring from our git repo to verify signatures on the release tags
-    export GNUPGHOME=$(git rev-parse --show-toplevel)/gnupg
+    GNUPGHOME=$(git rev-parse --show-toplevel)/gnupg
+    export GNUPGHOME
 
     NEWEST_SIGNED_TAG_UTIME=-1
     NEWEST_UNSIGNED_TAG_UTIME=-1
     for TAG in $(git tag -l "$GIT_TAG_GLOB"); do
-        if ! git cat-file tag $TAG > /dev/null 2> /dev/null; then
+        if ! git cat-file tag "$TAG" > /dev/null 2> /dev/null; then
             continue
         fi
 
-        TAG_UTIME=$(git cat-file tag $TAG | grep tagger | awk '{print $(NF-1)-$NF*36}')
+        TAG_UTIME=$(git cat-file tag "$TAG" | grep tagger | awk '{print $(NF-1)-$NF*36}')
 
         if git tag -v "$TAG" > /dev/null 2> /dev/null; then
             # it's a valid signed tag
-            if [ $TAG_UTIME -gt $NEWEST_SIGNED_TAG_UTIME ]; then
+            if [ "$TAG_UTIME" -gt "$NEWEST_SIGNED_TAG_UTIME" ]; then
                 NEWEST_SIGNED_TAG=$TAG
                 NEWEST_SIGNED_TAG_UTIME=$TAG_UTIME
             fi
         else
             # unsigned tag
-            if [ $TAG_UTIME -gt $NEWEST_UNSIGNED_TAG_UTIME ]; then
+            if [ "$TAG_UTIME" -gt "$NEWEST_UNSIGNED_TAG_UTIME" ]; then
                 NEWEST_UNSIGNED_TAG=$TAG
                 NEWEST_UNSIGNED_TAG_UTIME=$TAG_UTIME
             fi
@@ -78,13 +82,17 @@ function githelper() {
 
     done
 
-    if [ $NEWEST_SIGNED_TAG_UTIME -gt -1 ]; then
+    if [ "$NEWEST_SIGNED_TAG_UTIME" -gt -1 ]; then
+        # Disable unused variable warnings on GIT_TAG
+        # shellcheck disable=SC2034
         GIT_TAG="$NEWEST_SIGNED_TAG"
         return
     fi
 
-    if [ $NEWEST_UNSIGNED_TAG_UTIME -gt -1 ]; then
+    if [ "$NEWEST_UNSIGNED_TAG_UTIME" -gt -1 ]; then
         echo "no signed tags found, falling back to unsigned tags" > /dev/null 1>&2
+        # Disable unused variable warnings on GIT_TAG
+        # shellcheck disable=SC2034
         GIT_TAG="$NEWEST_UNSIGNED_TAG"
         return
     fi
diff --git a/scripts/gladevcp_demo b/scripts/gladevcp_demo
index 98f3ebc96cb..193c248f42c 100755
--- a/scripts/gladevcp_demo
+++ b/scripts/gladevcp_demo
@@ -23,7 +23,7 @@
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
-prog=$(basename $0)
+prog=$(basename "$0")
 
 function usage () {
   cat <<EOF
@@ -57,7 +57,7 @@ EOF
 REALTIME=$(linuxcnc_var REALTIME)
 $REALTIME status >/dev/null
 status=$?
-if [ $status = 0 ] ; then
+if [ "$status" = 0 ] ; then
   msg="$prog: Realtime is already active"
   echo "$msg"
   popup "$msg"
@@ -71,10 +71,10 @@ case $# in
   *) ARGS="$@";;
 esac
 
-if [ ! -z "$debug" ] ; then
-  echo debug=$debug
-  echo REALTIME=$REALTIME
-  echo ARGS="$ARGS"
+if [ -n "$debug" ] ; then
+  echo "debug=$debug"
+  echo "REALTIME=$REALTIME"
+  echo "ARGS=$ARGS"
 pwd
 fi
 
diff --git a/scripts/halrun.in b/scripts/halrun.in
index 63f4b8bde83..d3ee6383998 100644
--- a/scripts/halrun.in
+++ b/scripts/halrun.in
@@ -2,7 +2,7 @@
 
 PATH=@EMC2_BIN_DIR@:$PATH
 REALTIME=@REALTIME@
-THIS=$(basename $0)
+THIS=$(basename "$0")
 
 export HAL_RTMOD_DIR=@EMC2_RTLIB_DIR@
 
@@ -60,7 +60,7 @@ while getopts "ef:hi:kqsvIRQTUV" opt ; do
        exit 1;;
   esac
 done
-shift $(($OPTIND - 1))
+shift $((OPTIND - 1))
 
 if [ $# -gt 1 ] ; then
   echo "$THIS: too many arguments <$*>"
@@ -150,17 +150,17 @@ if $HAVEFILE ; then
         halcmd_twopass "$filename"; result=$?    
     fi
   elif $IS_HALTCL; then
-    haltcl $@; result=$?
+    haltcl "$@"; result=$?
   else
-    halcmd $@; result=$?
+    halcmd "$@"; result=$?
   fi
 fi
 
-if [ ! -z "$INTERACTIVE" ]; then $INTERACTIVE; fi
+if [ -n "$INTERACTIVE" ]; then $INTERACTIVE; fi
 
 halcmd stop || result=$?
 halcmd unload all || result=$?
 
 $REALTIME stop || result=$?
 
-exit $result
+exit "$result"
diff --git a/scripts/linuxcnc_info.in b/scripts/linuxcnc_info.in
index 668634114af..ac32e1ed319 100755
--- a/scripts/linuxcnc_info.in
+++ b/scripts/linuxcnc_info.in
@@ -21,7 +21,7 @@
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
 ofile=/tmp/linuxcnc_info.txt
-PROG=$(basename $0)
+PROG=$(basename "$0")
 
 usage () {
   cat <<EOF
@@ -36,11 +36,11 @@ exit 1
 }
 
 git_commit () {
-  dir=$(dirname $0)
+  dir=$(dirname "$0")
   if [ "${dir}" = "/usr/bin" ] ; then
     echo NA
   else
-    echo $(cd $dir; git rev-parse --short HEAD 2>/dev/null)
+    echo "$(cd "$dir" && git rev-parse --short HEAD 2>/dev/null)"
   fi
 }
 
@@ -49,7 +49,7 @@ git_commit () {
 editors="$VISUAL gedit mousepad geany nedit nano gvim abiword"
 VIEWER=""
 for e in $editors ; do
-  if [  -x "$(command -v $e)" ] ; then
+  if [  -x "$(command -v "$e")" ] ; then
     VIEWER=$e
     break #use first editor found
   fi
@@ -81,7 +81,7 @@ function show () {
 }
 
 function parse_cpuinfo () {
-  cat /proc/cpuinfo|grep "$1"|head -1|cut -d: -f2-
+  grep "$1" < /proc/cpuinfo | head -1 | cut -d: -f2-
 }
 
 function parse_after_colon () {
@@ -111,58 +111,58 @@ system and configuration.
 
 EOF
 
-[ -n "$VIEWER" ] && echo VIEWER=$VIEWER
-
-show "            Date" $(date)
-show "        UTC Date" $(date -u)
-show "    this program" $0
-show "          uptime" $(uptime)
-show " lsb_release -sa" $(lsb_release -sa 2>/dev/null)
-show "        linuxcnc" $(command -v linuxcnc)
-show "             pwd" $(pwd -P)
-show "            USER" $USER
-show "         LOGNAME" $LOGNAME
-show "            HOME" $HOME
-show "          EDITOR" $EDITOR
-show "          VISUAL" $VISUAL
-show "        LANGUAGE" $LANGUAGE
-show "            TERM" $TERM
-show "       COLORTERM" $COLORTERM
-show "         DISPLAY" $DISPLAY
-show "         DESKTOP" $DESKTOP_SESSION
-show "    display size" $(parse_after_colon $(xdpyinfo|grep dimensions))
-show "            PATH" $PATH
+[ -n "$VIEWER" ] && echo "VIEWER=$VIEWER"
+
+show "            Date" "$(date)"
+show "        UTC Date" "$(date -u)"
+show "    this program" "$0"
+show "          uptime" "$(uptime)"
+show " lsb_release -sa" "$(lsb_release -sa 2>/dev/null)"
+show "        linuxcnc" "$(command -v linuxcnc)"
+show "             pwd" "$(pwd -P)"
+show "            USER" "$USER"
+show "         LOGNAME" "$LOGNAME"
+show "            HOME" "$HOME"
+show "          EDITOR" "$EDITOR"
+show "          VISUAL" "$VISUAL"
+show "        LANGUAGE" "$LANGUAGE"
+show "            TERM" "$TERM"
+show "       COLORTERM" "$COLORTERM"
+show "         DISPLAY" "$DISPLAY"
+show "         DESKTOP" "$DESKTOP_SESSION"
+show "    display size" "$(parse_after_colon "$(xdpyinfo|grep dimensions)")"
+show "            PATH" "$PATH"
 echo
 echo "uname items:"
-show "     nodename -n" $(uname -n)
-show "  kernel-name -s" $(uname -s)
-show "  kernel-vers -v" $(uname -v)
-show "      machine -m" $(uname -m)
-show "    processor -p" $(uname -p)
-show "     platform -i" $(uname -i)
-show "  oper system -o" $(uname -o)
+show "     nodename -n" "$(uname -n)"
+show "  kernel-name -s" "$(uname -s)"
+show "  kernel-vers -v" "$(uname -v)"
+show "      machine -m" "$(uname -m)"
+show "    processor -p" "$(uname -p)"
+show "     platform -i" "$(uname -i)"
+show "  oper system -o" "$(uname -o)"
 show ""
 echo "/proc items:"
-show "         cmdline" $(< /proc/cmdline)
-show "      model name" $(parse_cpuinfo "model name")
-show "           cores" $(parse_cpuinfo "cpu cores")
-show "         cpu MHz" $(parse_cpuinfo "cpu MHz")
-show "         parport" $(cat /proc/ioports|grep parport)
-show "          serial" $(cat /proc/ioports|grep serial)
+show "         cmdline" "$(< /proc/cmdline)"
+show "      model name" "$(parse_cpuinfo "model name")"
+show "           cores" "$(parse_cpuinfo "cpu cores")"
+show "         cpu MHz" "$(parse_cpuinfo "cpu MHz")"
+show "         parport" "$(grep parport < /proc/ioports)"
+show "          serial" "$(grep serial < /proc/ioports)"
 echo
 echo "Versions:"
-show "             gcc" $(gcc --version|head -1)
-show "          python" $(@PYTHON@ --version 2>&1)
-show "             git" $(tryversion git)
-show "      git commit" $(git_commit)
-show "             tcl" $(echo "puts $::tcl_version"|tclsh)
-show "              tk" $(echo "puts $::tk_version;destroy ."|wish)
-show "           glade" $(tryversion glade)
+show "             gcc" "$(gcc --version|head -1)"
+show "          python" "$(@PYTHON@ --version 2>&1)"
+show "             git" "$(tryversion git)"
+show "      git commit" "$(git_commit)"
+show "             tcl" "$(echo "puts $::tcl_version"|tclsh)"
+show "              tk" "$(echo "puts $::tk_version;destroy ."|wish)"
+show "           glade" "$(tryversion glade)"
 echo
 echo "linuxcnc_var all:"
 echo
 for n in $(linuxcnc_var all) ; do
-   show "${n%%=*}" ${n##*=}
+   show "${n%%=*}" "${n##*=}"
 done
 
 echo
diff --git a/scripts/linuxcnc_var.in b/scripts/linuxcnc_var.in
index 3217a459d4e..9d4c835042e 100644
--- a/scripts/linuxcnc_var.in
+++ b/scripts/linuxcnc_var.in
@@ -25,7 +25,7 @@ function usage () {
 
 Retrieve Linuxcnc Variables
 Usage:
-      $(basename $0) [ varname | all ]
+      $(basename "$0") [ varname | all ]
 
 Varnames supported:
          LINUXCNCVERSION
@@ -67,7 +67,7 @@ function show_item () {
 
 case $# in
    0) usage;;
-   1) show_item $1;;
+   1) show_item "$1";;
    *) usage;;
 esac
 exit 0
diff --git a/scripts/man2adoc-migrate b/scripts/man2adoc-migrate
index 530a66a470c..fbc60759674 100755
--- a/scripts/man2adoc-migrate
+++ b/scripts/man2adoc-migrate
@@ -4,33 +4,33 @@
 
 # Convert all non-link manual pages to adoc
 for m in docs/man/man?/*; do
-    test -L $m && continue
-    n=$(echo $m |sed s%docs/man%docs/src/man%).adoc
-    if [ -e "$n" ] || [ -e "$n".in ] || grep -q '^.so' $m; then
-	echo "Not converting $m due to roff include or existing adoc version"
+    test -L "$m" && continue
+    n=$(echo "$m" |sed s%docs/man%docs/src/man%).adoc
+    if [ -e "$n" ] || [ -e "$n".in ] || grep -q '^.so' "$m"; then
+	echo "E: Not converting $m due to roff include or existing adoc version"
     else
-	echo "Converting $m to $n"
-        pandoc -f man -t asciidoc $m -o $n
-        git add $n
-        git rm --quiet $m
+	echo "I: Converting '$m' to '$n'"
+        pandoc -f man -t asciidoc "$m" -o "$n"
+        git add "$n"
+        git rm --quiet "$m"
     fi
 done
 
 # Make sure they can be converted back to manpage format
 for n in docs/src/man/man?/*.adoc; do
     #echo "Making sure $n got required header"
-    b=$(basename $n .adoc)
-    name=$(echo $b|cut -d. -f1)
-    s=$(echo $b|cut -d. -f2)
-    if ! head -1 $n | grep -q "= $name ($s)" ||
+    b=$(basename "$n" .adoc)
+    name=$(echo "$b"|cut -d. -f1)
+    s=$(echo "$b"|cut -d. -f2)
+    if ! head -1 "$n" | grep -q "= $name ($s)" ||
 	    ! "/usr/bin/asciidoc" --backend docbook \
               -a "a2x-format=manpage" --doctype manpage \
               --attribute "mansource=LinuxCNC" \
               --attribute "manmanual=LinuxCNC Documentation" \
               --verbose \
-              --out-file x.man $m
+              --out-file x.man "$m"
     then
-        (echo "= $name($s)"; echo; cat $n) > $n.new && mv $n.new $n
-        git add $n
+        (echo "= $name($s)"; echo; cat "$n") > "$n.new" && mv "$n.new" "$n"
+        git add "$n"
     fi
 done
diff --git a/scripts/rip-environment.in b/scripts/rip-environment.in
index 588c73b9a8f..692aa11ace0 100644
--- a/scripts/rip-environment.in
+++ b/scripts/rip-environment.in
@@ -49,7 +49,9 @@ case "$0" in
     *) as_command=false
 esac
 
-if ! test "xyes" = "x@RUN_IN_PLACE@"; then
+# This evaluates to [ "yes" = "yes" ], which is fine.
+# shellcheck disable=SC2050
+if [ "yes" != "@RUN_IN_PLACE@" ]; then
     echo "This script is only useful on run-in-place systems."
     return
 fi
@@ -69,7 +71,7 @@ LINUXCNCVERSION="@EMC2VERSION@"; export LINUXCNCVERSION
 LINUXCNC_NCFILES_DIR="@EMC2_NCFILES_DIR@"; export LINUXCNC_NCFILES_DIR
 LINUXCNC_EMCSH=@WISH@; export LINUXCNC_EMCSH
 PATH=@EMC2_BIN_DIR@:$EMC2_HOME/scripts:$EMC2_HOME/tcl:"$PATH"
-GLADE_ICON_THEME_PATH=$EMC2_HOME/share/glade/pixmaps:"$GLADE_ICON_THEME_PATH" export GLADE_ICON_THEME_PATH
+GLADE_ICON_THEME_PATH=$EMC2_HOME/share/glade/pixmaps:"$GLADE_ICON_THEME_PATH"; export GLADE_ICON_THEME_PATH
 
 if [ -z "$TCLLIBPATH" ]; then
     TCLLIBPATH=$EMC2_HOME/tcl
@@ -108,7 +110,7 @@ fi
 if ! $as_command; then
     # TODO: if these completion directives give trouble for any versions
     # of bash actively in use, protect them with checks of BASH_VERSINFO
-    if [ $BASH_VERSINFO -eq 2 ]; then
+    if [ "${BASH_VERSINFO[0]}" -eq 2 ]; then
         complete -o dirnames -f -X '!*.ini' emc axis mdi
         complete -o dirnames -f -X '!*.hal' halrun halcmd
         complete -W 'start stop restart status' realtime
@@ -127,8 +129,8 @@ if ! $as_command; then
         complete -C "halcmd -C" halcmd
     fi
 
-    if [ -f $EMC2_HOME/src/Makefile ]; then
-        build () { make -C $EMC2_HOME/src "$@"; }
+    if [ -f "$EMC2_HOME/src/Makefile" ]; then
+        build () { make -C "$EMC2_HOME/src" "$@"; }
     fi
 fi
 
diff --git a/scripts/travis-build-test.sh b/scripts/travis-build-test.sh
index 2a91ae333fe..667a94930ed 100755
--- a/scripts/travis-build-test.sh
+++ b/scripts/travis-build-test.sh
@@ -2,7 +2,7 @@
 cd src
 ./autogen.sh
 ./configure --disable-check-runtime-deps --enable-build-documentation
-make -O -j$(getconf _NPROCESSORS_ONLN) manpages V=1
-make -O -j$(getconf _NPROCESSORS_ONLN) translateddocs V=1
-make -O -j$(getconf _NPROCESSORS_ONLN) default pycheck V=1
+make -O -j"$(getconf _NPROCESSORS_ONLN)" manpages V=1
+make -O -j"$(getconf _NPROCESSORS_ONLN)" translateddocs V=1
+make -O -j"$(getconf _NPROCESSORS_ONLN)" default pycheck V=1
 ../scripts/rip-environment runtests
diff --git a/scripts/version-is-release b/scripts/version-is-release
index 9e2cfea5409..b73f963b02e 100755
--- a/scripts/version-is-release
+++ b/scripts/version-is-release
@@ -8,23 +8,23 @@
 # that is signed by the release manager's key.
 #
 
-if [ ! -z "$EMC2_HOME" ]; then
-    source $EMC2_HOME/scripts/githelper.sh
+if [ -n "$EMC2_HOME" ]; then
+    source "$EMC2_HOME"/scripts/githelper.sh
 else
-    source $(git rev-parse --show-toplevel)/scripts/githelper.sh
+    source "$(git rev-parse --show-toplevel)"/scripts/githelper.sh
 fi
 
-githelper $1
+githelper "$1"
 if [ -z "$GIT_TAG" ]; then
     # no signed tags found
     echo "no"
     exit 1
 fi
 
-TAGGED_REV=$(git rev-parse $GIT_TAG^{commit})
+TAGGED_REV=$(git rev-parse "$GIT_TAG^{commit}")
 HEAD_REV=$(git rev-parse HEAD)
 
-if [ "$TAGGED_REV" == "$HEAD_REV" ]; then
+if [ "$TAGGED_REV" = "$HEAD_REV" ]; then
     echo "yes"
     exit 0
 fi
diff --git a/scripts/xhc-hb04-accels b/scripts/xhc-hb04-accels
index 4497a6848d0..dad4d3a9d22 100755
--- a/scripts/xhc-hb04-accels
+++ b/scripts/xhc-hb04-accels
@@ -3,7 +3,7 @@
 cat << EOF
 #------------------------------------------------------------
 This obsolete script:
-   $(basename $0)
+   $(basename "$0")
 should be removed from LinuxCNC ini files (effective 2.8~pre)
 
 xhc-hb04.tcl now controls reduced wheel jogging accels using
diff --git a/share/qtvcp/screens/qtdragon/languages/langfile b/share/qtvcp/screens/qtdragon/languages/langfile
index ae06792d9c5..df36da9ca10 100755
--- a/share/qtvcp/screens/qtdragon/languages/langfile
+++ b/share/qtvcp/screens/qtdragon/languages/langfile
@@ -8,6 +8,6 @@ elif [ ${#1} -ne 2 ]; then
     exit
 fi
 
-echo -e '\ncreating language translation file qtdragon_'$1'.ts\n'
+echo -e '\ncreating language translation file qtdragon_'"$1"'.ts\n'
 
-pylupdate5 *.py ../*.py  -ts qtdragon_$1.ts
+pylupdate5 ./*.py ../*.py  -ts "qtdragon_$1.ts"
diff --git a/share/qtvcp/screens/qtdragon_hd/languages/langfile b/share/qtvcp/screens/qtdragon_hd/languages/langfile
index b7af179051c..776253d6361 100755
--- a/share/qtvcp/screens/qtdragon_hd/languages/langfile
+++ b/share/qtvcp/screens/qtdragon_hd/languages/langfile
@@ -8,6 +8,6 @@ elif [ ${#1} -ne 2 ]; then
     exit
 fi
 
-echo -e '\ncreating language translation file qtdragon_hd_'$1'.ts\n'
+echo -e '\ncreating language translation file qtdragon_hd_'"$1"'.ts\n'
 
-pylupdate5 *.py ../*.py  -ts qtdragon_hd_$1.ts
+pylupdate5 ./*.py ../*.py  -ts "qtdragon_hd_$1.ts"
diff --git a/share/qtvcp/screens/qtdragon_lathe/languages/langfile b/share/qtvcp/screens/qtdragon_lathe/languages/langfile
index 852113ec230..c07af65f0e5 100755
--- a/share/qtvcp/screens/qtdragon_lathe/languages/langfile
+++ b/share/qtvcp/screens/qtdragon_lathe/languages/langfile
@@ -8,6 +8,6 @@ elif [ ${#1} -ne 2 ]; then
     exit
 fi
 
-echo -e '\ncreating language translation file qtdragon_lathe_'$1'.ts\n'
+echo -e '\ncreating language translation file qtdragon_lathe_'"$1"'.ts\n'
 
-pylupdate5 *.py ../*.py  -ts qtdragon_lathe_$1.ts
+pylupdate5 ./*.py ../*.py  -ts "qtdragon_lathe_$1.ts"
diff --git a/share/qtvcp/screens/qtplasmac/languages/langfile b/share/qtvcp/screens/qtplasmac/languages/langfile
index bc0cafb0b5e..f3e2eeb812e 100755
--- a/share/qtvcp/screens/qtplasmac/languages/langfile
+++ b/share/qtvcp/screens/qtplasmac/languages/langfile
@@ -12,4 +12,4 @@ fi
 
 echo -e "\ncreating language translation file qtplasmac_$1.ts\n"
 
-pylupdate5 *.py ../*.py ../../../../../lib/python/qtvcp/lib/qtplasmac/*.py -ts qtplasmac_$1.ts
+pylupdate5 ./*.py ../*.py ../../../../../lib/python/qtvcp/lib/qtplasmac/*.py -ts "qtplasmac_$1.ts"
diff --git a/share/qtvcp/screens/qtplasmac/languages/langlink b/share/qtvcp/screens/qtplasmac/languages/langlink
index 109decd4e1e..7a94145c784 100755
--- a/share/qtvcp/screens/qtplasmac/languages/langlink
+++ b/share/qtvcp/screens/qtplasmac/languages/langlink
@@ -19,8 +19,8 @@ else
     echo -e "\ncreating links to qtplasmac_$1.qn translation for qtplasmac_4x3 and qtplasmac_9x16\n"
     mkdir -p "../../qtplasmac_4x3/languages"
     mkdir -p "../../qtplasmac_9x16/languages"
-    ln -rs qtplasmac_$1.qm -t ../../qtplasmac_4x3/languages
-    ln -rs qtplasmac_$1.qm -t ../../qtplasmac_9x16/languages
-    mv ../../qtplasmac_4x3/languages/qtplasmac_$1.qm ../../qtplasmac_4x3/languages/qtplasmac_4x3_sk.qm
-    mv ../../qtplasmac_9x16/languages/qtplasmac_$1.qm ../../qtplasmac_9x16/languages/qtplasmac_9x16_sk.qm
+    ln -rs "qtplasmac_$1.qm" -t ../../qtplasmac_4x3/languages
+    ln -rs "qtplasmac_$1.qm" -t ../../qtplasmac_9x16/languages
+    mv "../../qtplasmac_4x3/languages/qtplasmac_$1.qm" ../../qtplasmac_4x3/languages/qtplasmac_4x3_sk.qm
+    mv "../../qtplasmac_9x16/languages/qtplasmac_$1.qm" ../../qtplasmac_9x16/languages/qtplasmac_9x16_sk.qm
 fi
diff --git a/src/autogen.sh b/src/autogen.sh
index 701ca82dd22..11e68c8d3ec 100755
--- a/src/autogen.sh
+++ b/src/autogen.sh
@@ -4,10 +4,10 @@ AUTOGEN_TARGET=${AUTOGEN_TARGET-configure:config.h.in}
 set -e
 case :$AUTOGEN_TARGET: in
 *:configure:*)
-    automake_libdir=`automake --print-libdir`
-    [ -e config.guess ] || cp $automake_libdir/config.guess .
-    [ -e config.sub ] || cp $automake_libdir/config.sub .
-    [ -e install-sh ] || cp $automake_libdir/install-sh .
+    automake_libdir=$(automake --print-libdir)
+    [ -e config.guess ] || cp "$automake_libdir/config.guess" .
+    [ -e config.sub ] || cp "$automake_libdir/config.sub" .
+    [ -e install-sh ] || cp "$automake_libdir/install-sh" .
     aclocal --force
     autoconf
     # autoconf only updates the timestamp if the output actually changed.
diff --git a/tests/ccomp/lathe-comp/test.sh b/tests/ccomp/lathe-comp/test.sh
index b631a39327a..f74438f2b88 100644
--- a/tests/ccomp/lathe-comp/test.sh
+++ b/tests/ccomp/lathe-comp/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -t test.tbl -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/ccomp/mill-g90g91g92/test.sh b/tests/ccomp/mill-g90g91g92/test.sh
index b631a39327a..f74438f2b88 100644
--- a/tests/ccomp/mill-g90g91g92/test.sh
+++ b/tests/ccomp/mill-g90g91g92/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -t test.tbl -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/ccomp/mill-line-arc-entry/test.sh b/tests/ccomp/mill-line-arc-entry/test.sh
index b631a39327a..f74438f2b88 100644
--- a/tests/ccomp/mill-line-arc-entry/test.sh
+++ b/tests/ccomp/mill-line-arc-entry/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -t test.tbl -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/ccomp/mill-zchanges/test.sh b/tests/ccomp/mill-zchanges/test.sh
index b631a39327a..f74438f2b88 100644
--- a/tests/ccomp/mill-zchanges/test.sh
+++ b/tests/ccomp/mill-zchanges/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -t test.tbl -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/classicladder/estop/checkresult b/tests/classicladder/estop/checkresult
index 4ad0f2d568f..12395f0c429 100755
--- a/tests/classicladder/estop/checkresult
+++ b/tests/classicladder/estop/checkresult
@@ -2,7 +2,7 @@
 
 result=$1
 
-if grep -qi error: $result ; then
+if grep -qi error: "$result" ; then
     echo "found string 'error' in $result"
     exit 1
 fi
diff --git a/tests/classicladder/estop/test.sh b/tests/classicladder/estop/test.sh
index 2affbde136c..28fed652630 100755
--- a/tests/classicladder/estop/test.sh
+++ b/tests/classicladder/estop/test.sh
@@ -7,4 +7,4 @@
 if [ "libeatmydata.so" = "$LD_PRELOAD" ] ; then
     unset LD_PRELOAD
 fi
-exec linuxcnc $(dirname $0)/classicladder-estop.ini
+exec linuxcnc "$(dirname "$0")/classicladder-estop.ini"
diff --git a/tests/halcompile/extralib/checkresult b/tests/halcompile/extralib/checkresult
index 610bf2cbf08..b4f3cc1a643 100755
--- a/tests/halcompile/extralib/checkresult
+++ b/tests/halcompile/extralib/checkresult
@@ -1,2 +1,2 @@
 #!/bin/sh
-[ -x "`dirname "$1"`/extralib_test" ]
+[ -x "$(dirname "$1")/extralib_test" ]
diff --git a/tests/halcompile/userspace/checkresult b/tests/halcompile/userspace/checkresult
index 6936818f423..f5d9795d155 100755
--- a/tests/halcompile/userspace/checkresult
+++ b/tests/halcompile/userspace/checkresult
@@ -1,2 +1,2 @@
 #!/bin/sh
-[ -x $(dirname $1)/rand_test ]
+[ -x "$(dirname "$1")/rand_test" ]
diff --git a/tests/interp/cam-nisley/test.sh b/tests/interp/cam-nisley/test.sh
index 3ee34072b1b..4440735bfae 100644
--- a/tests/interp/cam-nisley/test.sh
+++ b/tests/interp/cam-nisley/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -t test.tbl -g cam.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/crazy-paths/test.sh b/tests/interp/crazy-paths/test.sh
index 83d69e365c8..2afa80d1ca5 100644
--- a/tests/interp/crazy-paths/test.sh
+++ b/tests/interp/crazy-paths/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/do-while-break/test.sh b/tests/interp/do-while-break/test.sh
index 83d69e365c8..2afa80d1ca5 100644
--- a/tests/interp/do-while-break/test.sh
+++ b/tests/interp/do-while-break/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/exists/test.sh b/tests/interp/exists/test.sh
index 83d69e365c8..2afa80d1ca5 100644
--- a/tests/interp/exists/test.sh
+++ b/tests/interp/exists/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/flowsnake/test.sh b/tests/interp/flowsnake/test.sh
index 68e5ed2082f..18893aab433 100644
--- a/tests/interp/flowsnake/test.sh
+++ b/tests/interp/flowsnake/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g flowsnake.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/fractional-linenumbers/test.sh b/tests/interp/fractional-linenumbers/test.sh
index 83d69e365c8..2afa80d1ca5 100644
--- a/tests/interp/fractional-linenumbers/test.sh
+++ b/tests/interp/fractional-linenumbers/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/g10/g10-l1-l10/test.sh b/tests/interp/g10/g10-l1-l10/test.sh
index 29ef11d7a75..52077f363e2 100755
--- a/tests/interp/g10/g10-l1-l10/test.sh
+++ b/tests/interp/g10/g10-l1-l10/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc -t test.tbl | awk '{$1=""; print}' | sed 's/-0\.0000/0.0000/g'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/g10/g10-l11/test.sh b/tests/interp/g10/g10-l11/test.sh
index 29ef11d7a75..52077f363e2 100755
--- a/tests/interp/g10/g10-l11/test.sh
+++ b/tests/interp/g10/g10-l11/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc -t test.tbl | awk '{$1=""; print}' | sed 's/-0\.0000/0.0000/g'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/g10/g10-l2-while-active/test.sh b/tests/interp/g10/g10-l2-while-active/test.sh
index 83d69e365c8..2afa80d1ca5 100755
--- a/tests/interp/g10/g10-l2-while-active/test.sh
+++ b/tests/interp/g10/g10-l2-while-active/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/g10/g10-l20-while-active/test.sh b/tests/interp/g10/g10-l20-while-active/test.sh
index 6d4141e75aa..65bddf51a33 100755
--- a/tests/interp/g10/g10-l20-while-active/test.sh
+++ b/tests/interp/g10/g10-l20-while-active/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}' | sed 's/-0\.0000/0.0000/g'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/g10/g10-with-g92/test.sh b/tests/interp/g10/g10-with-g92/test.sh
index 8fa0c30ded8..69ec8bee746 100755
--- a/tests/interp/g10/g10-with-g92/test.sh
+++ b/tests/interp/g10/g10-with-g92/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc -t test.tbl | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/g33.1/test.sh b/tests/interp/g33.1/test.sh
index 5a9af07688e..574a4921f8a 100644
--- a/tests/interp/g33.1/test.sh
+++ b/tests/interp/g33.1/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g g33.1.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/g6164/test.sh b/tests/interp/g6164/test.sh
index 83d69e365c8..2afa80d1ca5 100644
--- a/tests/interp/g6164/test.sh
+++ b/tests/interp/g6164/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/g76/test.sh b/tests/interp/g76/test.sh
index e5c98955404..1993dcb1c88 100644
--- a/tests/interp/g76/test.sh
+++ b/tests/interp/g76/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -t test.tbl -g g76only.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/g81/g17/g98/test.sh b/tests/interp/g81/g17/g98/test.sh
index 3aa65b53475..214cd02540e 100644
--- a/tests/interp/g81/g17/g98/test.sh
+++ b/tests/interp/g81/g17/g98/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g g17-g98-g81.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/g81/g17/g99/test.sh b/tests/interp/g81/g17/g99/test.sh
index 466c7243a0c..f4f8fec3660 100644
--- a/tests/interp/g81/g17/g99/test.sh
+++ b/tests/interp/g81/g17/g99/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g g17-g99-g81.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/g81/g18/g98/test.sh b/tests/interp/g81/g18/g98/test.sh
index 8828e2e9319..056ffb5014e 100644
--- a/tests/interp/g81/g18/g98/test.sh
+++ b/tests/interp/g81/g18/g98/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g g18-g98-g81.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/g81/g18/g99/test.sh b/tests/interp/g81/g18/g99/test.sh
index 4de0eb0743c..1eba671e2f8 100644
--- a/tests/interp/g81/g18/g99/test.sh
+++ b/tests/interp/g81/g18/g99/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g g18-g99-g81.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/g81/g19/g98/test.sh b/tests/interp/g81/g19/g98/test.sh
index d4f14b95f46..a10d41f6953 100644
--- a/tests/interp/g81/g19/g98/test.sh
+++ b/tests/interp/g81/g19/g98/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g g19-g98-g81.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/g81/g19/g99/test.sh b/tests/interp/g81/g19/g99/test.sh
index 69187669c25..ef2c0ac2ac0 100644
--- a/tests/interp/g81/g19/g99/test.sh
+++ b/tests/interp/g81/g19/g99/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g g19-g99-g81.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/g84/g17/g98/test.sh b/tests/interp/g84/g17/g98/test.sh
index 601e4ada81f..5a43938a92b 100755
--- a/tests/interp/g84/g17/g98/test.sh
+++ b/tests/interp/g84/g17/g98/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g g17-g98-g84.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/g84/g17/g99/test.sh b/tests/interp/g84/g17/g99/test.sh
index ab358fce49a..5b95133f8e3 100644
--- a/tests/interp/g84/g17/g99/test.sh
+++ b/tests/interp/g84/g17/g99/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g g17-g99-g84.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/g84/g18/g98/test.sh b/tests/interp/g84/g18/g98/test.sh
index 9110de97652..0b60af3801d 100644
--- a/tests/interp/g84/g18/g98/test.sh
+++ b/tests/interp/g84/g18/g98/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g g18-g98-g84.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/g84/g18/g99/test.sh b/tests/interp/g84/g18/g99/test.sh
index b7008b70fb0..f946371d20e 100644
--- a/tests/interp/g84/g18/g99/test.sh
+++ b/tests/interp/g84/g18/g99/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g g18-g99-g84.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/g84/g19/g98/test.sh b/tests/interp/g84/g19/g98/test.sh
index 9b0806ee414..4545239caee 100644
--- a/tests/interp/g84/g19/g98/test.sh
+++ b/tests/interp/g84/g19/g98/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g g19-g98-g84.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/g84/g19/g99/test.sh b/tests/interp/g84/g19/g99/test.sh
index 16e5a42673a..e82c38e1084 100644
--- a/tests/interp/g84/g19/g99/test.sh
+++ b/tests/interp/g84/g19/g99/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g g19-g99-g84.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/inside-corners/test.sh b/tests/interp/inside-corners/test.sh
index 83d69e365c8..2afa80d1ca5 100644
--- a/tests/interp/inside-corners/test.sh
+++ b/tests/interp/inside-corners/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/inverse-time-with-comp/test.sh b/tests/interp/inverse-time-with-comp/test.sh
index 9279a98e2f2..cec720fe1f7 100644
--- a/tests/interp/inverse-time-with-comp/test.sh
+++ b/tests/interp/inverse-time-with-comp/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g inverse.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/m19/test.sh b/tests/interp/m19/test.sh
index da351514599..22f60fd0ac7 100644
--- a/tests/interp/m19/test.sh
+++ b/tests/interp/m19/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -n 0 -i test.ini -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/m98m99/01-basics/test.sh b/tests/interp/m98m99/01-basics/test.sh
index 83d69e365c8..2afa80d1ca5 100755
--- a/tests/interp/m98m99/01-basics/test.sh
+++ b/tests/interp/m98m99/01-basics/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/m98m99/02-variables/test.sh b/tests/interp/m98m99/02-variables/test.sh
index 83d69e365c8..2afa80d1ca5 100644
--- a/tests/interp/m98m99/02-variables/test.sh
+++ b/tests/interp/m98m99/02-variables/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/m98m99/05-M98-loops/test.sh b/tests/interp/m98m99/05-M98-loops/test.sh
index 83d69e365c8..2afa80d1ca5 100644
--- a/tests/interp/m98m99/05-M98-loops/test.sh
+++ b/tests/interp/m98m99/05-M98-loops/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/m98m99/07-nested-subs/test.sh b/tests/interp/m98m99/07-nested-subs/test.sh
index 83d69e365c8..2afa80d1ca5 100644
--- a/tests/interp/m98m99/07-nested-subs/test.sh
+++ b/tests/interp/m98m99/07-nested-subs/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/m98m99/08-sub-follows-main/test.sh b/tests/interp/m98m99/08-sub-follows-main/test.sh
index 83d69e365c8..2afa80d1ca5 100644
--- a/tests/interp/m98m99/08-sub-follows-main/test.sh
+++ b/tests/interp/m98m99/08-sub-follows-main/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/m98m99/10-M98-P001/test.sh b/tests/interp/m98m99/10-M98-P001/test.sh
index 83d69e365c8..2afa80d1ca5 100644
--- a/tests/interp/m98m99/10-M98-P001/test.sh
+++ b/tests/interp/m98m99/10-M98-P001/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/m98m99/11-main-program-oword/test.sh b/tests/interp/m98m99/11-main-program-oword/test.sh
index 448dc119130..34c1b2b1f71 100644
--- a/tests/interp/m98m99/11-main-program-oword/test.sh
+++ b/tests/interp/m98m99/11-main-program-oword/test.sh
@@ -18,7 +18,7 @@ ILLEGAL_TESTS="
 #
 for t in $LEGAL_TESTS; do
     echo "Legal test ${t}:"
-    rs274 -g test-legal-${t}.ngc | awk '{$1=""; print}'
+    rs274 -g "test-legal-${t}.ngc" | awk '{$1=""; print}'
     res=${PIPESTATUS[0]}
     if test "$res" = 0; then
 	echo "Success: Test '${t}' exited ${res}" >&2
@@ -33,7 +33,7 @@ done
 for t in $ILLEGAL_TESTS; do
     echo "Illegal test ${t}:"
     res=-1
-    rs274 -g test-illegal-${t}.ngc | awk '{$1=""; print}'
+    rs274 -g "test-illegal-${t}.ngc" | awk '{$1=""; print}'
     res=${PIPESTATUS[0]}
     if test "$res" = 0; then
 	echo "Error: Illegal test '${t}' exited ${res}" >&2
diff --git a/tests/interp/m98m99/12-M99-endless-main-program/test.sh b/tests/interp/m98m99/12-M99-endless-main-program/test.sh
index 9a0ef1271f3..7ef57534546 100755
--- a/tests/interp/m98m99/12-M99-endless-main-program/test.sh
+++ b/tests/interp/m98m99/12-M99-endless-main-program/test.sh
@@ -7,4 +7,4 @@ linuxcnc -r motion-logger.ini
 
 # Run test file in stand-alone interpreter:  should run program once
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/magic_comments/param_format_printing/test.sh b/tests/interp/magic_comments/param_format_printing/test.sh
index 83d69e365c8..2afa80d1ca5 100644
--- a/tests/interp/magic_comments/param_format_printing/test.sh
+++ b/tests/interp/magic_comments/param_format_printing/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/namedparam-bug424/test.sh b/tests/interp/namedparam-bug424/test.sh
index 83d69e365c8..2afa80d1ca5 100644
--- a/tests/interp/namedparam-bug424/test.sh
+++ b/tests/interp/namedparam-bug424/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/oword-bug315-p2/test.sh b/tests/interp/oword-bug315-p2/test.sh
index 83d69e365c8..2afa80d1ca5 100644
--- a/tests/interp/oword-bug315-p2/test.sh
+++ b/tests/interp/oword-bug315-p2/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/oword-bug315/test.sh b/tests/interp/oword-bug315/test.sh
index 83d69e365c8..2afa80d1ca5 100644
--- a/tests/interp/oword-bug315/test.sh
+++ b/tests/interp/oword-bug315/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/oword-unwind/test.sh b/tests/interp/oword-unwind/test.sh
index da351514599..22f60fd0ac7 100644
--- a/tests/interp/oword-unwind/test.sh
+++ b/tests/interp/oword-unwind/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -n 0 -i test.ini -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/plug/absolute/test.sh b/tests/interp/plug/absolute/test.sh
index 7d29952328b..7044c07bf33 100644
--- a/tests/interp/plug/absolute/test.sh
+++ b/tests/interp/plug/absolute/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -p "${LIBDIR}"/linuxcnc/canterp.so -g canon | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/plug/filename/test.sh b/tests/interp/plug/filename/test.sh
index 40043f9edd3..e6c1a20e9a4 100644
--- a/tests/interp/plug/filename/test.sh
+++ b/tests/interp/plug/filename/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -p canterp.so -g canon | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/plug/relative/test.sh b/tests/interp/plug/relative/test.sh
index defb33cfdb0..55db7ddb4b5 100644
--- a/tests/interp/plug/relative/test.sh
+++ b/tests/interp/plug/relative/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -p ./canterp.so -g canon | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/python/error/checkresult b/tests/interp/python/error/checkresult
index 1c9f2d03137..796ccb36769 100755
--- a/tests/interp/python/error/checkresult
+++ b/tests/interp/python/error/checkresult
@@ -1,2 +1,2 @@
 #!/bin/sh
-grep -q -F 'Radius to end of arc differs from radius to start:' $1
+grep -q -F 'Radius to end of arc differs from radius to start:' "$1"
diff --git a/tests/interp/return-value/test.sh b/tests/interp/return-value/test.sh
index 83d69e365c8..2afa80d1ca5 100644
--- a/tests/interp/return-value/test.sh
+++ b/tests/interp/return-value/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/rotation/abs-pts/test.sh b/tests/interp/rotation/abs-pts/test.sh
index 5b214441322..53e9013752c 100644
--- a/tests/interp/rotation/abs-pts/test.sh
+++ b/tests/interp/rotation/abs-pts/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc -t test.tbl | awk '/MESSAGE/ {$1=""; print}' | sed 's/-0\.0000/0.0000/g'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/rotation/g28/test.sh b/tests/interp/rotation/g28/test.sh
index 33218bea6ab..998595ed67e 100755
--- a/tests/interp/rotation/g28/test.sh
+++ b/tests/interp/rotation/g28/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g g28.ngc | sed 's/-0\.0000/0.0000/g'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/rotation/g53/test.sh b/tests/interp/rotation/g53/test.sh
index ac5b7fe17a5..8ced2f78e4b 100755
--- a/tests/interp/rotation/g53/test.sh
+++ b/tests/interp/rotation/g53/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g g53.ngc | sed 's/-0\.0000/0.0000/g'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/interp/subs-follow-main/test.sh b/tests/interp/subs-follow-main/test.sh
index 83d69e365c8..2afa80d1ca5 100644
--- a/tests/interp/subs-follow-main/test.sh
+++ b/tests/interp/subs-follow-main/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/linuxcncrsh-tcp/subs/M100 b/tests/linuxcncrsh-tcp/subs/M100
index 77d6be2b712..ab0e0d2f1a0 100755
--- a/tests/linuxcncrsh-tcp/subs/M100
+++ b/tests/linuxcncrsh-tcp/subs/M100
@@ -15,6 +15,6 @@ OUT_FILE=$TEST_DIR/gcode-output
 P=$1
 Q=$2
 
-echo P is $P >> $OUT_FILE
-echo Q is $Q >> $OUT_FILE
+echo "P is $P" >> "$OUT_FILE"
+echo "Q is $Q" >> "$OUT_FILE"
 
diff --git a/tests/linuxcncrsh-tcp/test.sh b/tests/linuxcncrsh-tcp/test.sh
index a8da4840ac4..9683b8e7eb6 100755
--- a/tests/linuxcncrsh-tcp/test.sh
+++ b/tests/linuxcncrsh-tcp/test.sh
@@ -13,41 +13,41 @@ linuxcnc -r linuxcncrsh-test.ini &
 # let linuxcnc come up
 TOGO=80
 while [  $TOGO -gt 0 ]; do
-    echo trying to connect to linuxcncrsh TOGO=$TOGO
+    echo "trying to connect to linuxcncrsh TOGO=$TOGO"
     if nc -z localhost 5007; then
         break
     fi
     sleep 0.25
-    TOGO=$(($TOGO - 1))
+    TOGO=$((TOGO - 1))
 done
 if [  $TOGO -eq 0 ]; then
-    echo connection to linuxcncrsh timed out
+    echo "connection to linuxcncrsh timed out"
     exit 1
 fi
 
 
 (
-    echo hello EMC mt 1.0
-    echo set enable EMCTOO
+    echo "hello EMC mt 1.0"
+    echo "set enable EMCTOO"
 
     # ask linuxcncrsh to not read the next command until it's done running
     # the current one
-    echo set set_wait done
+    echo "set set_wait done"
 
-    echo set mode manual
-    echo set estop off
-    echo set machine on
+    echo "set mode manual"
+    echo "set estop off"
+    echo "set machine on"
 
-    echo set mode mdi
-    echo set mdi m100 p-1 q-2
+    echo "set mode mdi"
+    echo "set mdi m100 p-1 q-2"
     sleep 1
 
     # here comes a big blob
     dd bs=4096 if=lots-of-gcode
 
-    echo set mdi m100 p-3 q-4
+    echo "set mdi m100 p-3 q-4"
 
-    echo shutdown
+    echo "shutdown"
 ) | nc localhost 5007
 
 
diff --git a/tests/linuxcncrsh/subs/M100 b/tests/linuxcncrsh/subs/M100
index 77d6be2b712..ab0e0d2f1a0 100755
--- a/tests/linuxcncrsh/subs/M100
+++ b/tests/linuxcncrsh/subs/M100
@@ -15,6 +15,6 @@ OUT_FILE=$TEST_DIR/gcode-output
 P=$1
 Q=$2
 
-echo P is $P >> $OUT_FILE
-echo Q is $Q >> $OUT_FILE
+echo "P is $P" >> "$OUT_FILE"
+echo "Q is $Q" >> "$OUT_FILE"
 
diff --git a/tests/m70-m73/m70m72-restore.0/test.sh b/tests/m70-m73/m70m72-restore.0/test.sh
index 83d69e365c8..2afa80d1ca5 100644
--- a/tests/m70-m73/m70m72-restore.0/test.sh
+++ b/tests/m70-m73/m70m72-restore.0/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/m70-m73/m73-flood-mist-restore.0/test.sh b/tests/m70-m73/m73-flood-mist-restore.0/test.sh
index 83d69e365c8..2afa80d1ca5 100644
--- a/tests/m70-m73/m73-flood-mist-restore.0/test.sh
+++ b/tests/m70-m73/m73-flood-mist-restore.0/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/m70-m73/m73autorestore.0/test.sh b/tests/m70-m73/m73autorestore.0/test.sh
index 83d69e365c8..2afa80d1ca5 100644
--- a/tests/m70-m73/m73autorestore.0/test.sh
+++ b/tests/m70-m73/m73autorestore.0/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/mb2hal/mb2hal.1a/checkresult b/tests/mb2hal/mb2hal.1a/checkresult
index e9b32e7c804..239e74506f3 100755
--- a/tests/mb2hal/mb2hal.1a/checkresult
+++ b/tests/mb2hal/mb2hal.1a/checkresult
@@ -1,7 +1,7 @@
 #!/bin/bash
 set -e
 
-TESTDIR=$(dirname $1)
+TESTDIR=$(dirname "$1")
 cd "${TESTDIR}"
 
 # HAL assigns each component a unique component ID at load-time.
diff --git a/tests/mb2hal/mb2hal.1b/checkresult b/tests/mb2hal/mb2hal.1b/checkresult
index 4d5cba97b00..39dde14e13a 100755
--- a/tests/mb2hal/mb2hal.1b/checkresult
+++ b/tests/mb2hal/mb2hal.1b/checkresult
@@ -1,7 +1,7 @@
 #!/bin/bash
 set -e
 
-TESTDIR=$(dirname $1)
+TESTDIR=$(dirname "$1")
 cd "${TESTDIR}"
 
 # HAL assigns each component a unique component ID at load-time.
diff --git a/tests/mb2hal/mb2hal.2a/checkresult b/tests/mb2hal/mb2hal.2a/checkresult
index e9b32e7c804..239e74506f3 100755
--- a/tests/mb2hal/mb2hal.2a/checkresult
+++ b/tests/mb2hal/mb2hal.2a/checkresult
@@ -1,7 +1,7 @@
 #!/bin/bash
 set -e
 
-TESTDIR=$(dirname $1)
+TESTDIR=$(dirname "$1")
 cd "${TESTDIR}"
 
 # HAL assigns each component a unique component ID at load-time.
diff --git a/tests/mb2hal/mb2hal.2b/checkresult b/tests/mb2hal/mb2hal.2b/checkresult
index 4d5cba97b00..39dde14e13a 100755
--- a/tests/mb2hal/mb2hal.2b/checkresult
+++ b/tests/mb2hal/mb2hal.2b/checkresult
@@ -1,7 +1,7 @@
 #!/bin/bash
 set -e
 
-TESTDIR=$(dirname $1)
+TESTDIR=$(dirname "$1")
 cd "${TESTDIR}"
 
 # HAL assigns each component a unique component ID at load-time.
diff --git a/tests/mdi-queue/subs/M100 b/tests/mdi-queue/subs/M100
index 85f6204dca8..20e1906d210 100755
--- a/tests/mdi-queue/subs/M100
+++ b/tests/mdi-queue/subs/M100
@@ -13,5 +13,5 @@ OUT_FILE=$TEST_DIR/gcode-output
 
 P=$1
 
-echo P is $P >> $OUT_FILE
+echo "P is $P" >> "$OUT_FILE"
 
diff --git a/tests/module-loading/rtapi-app-main-fails/checkresult b/tests/module-loading/rtapi-app-main-fails/checkresult
index 5b646386e8d..559b534ae51 100755
--- a/tests/module-loading/rtapi-app-main-fails/checkresult
+++ b/tests/module-loading/rtapi-app-main-fails/checkresult
@@ -1,19 +1,19 @@
 #!/bin/sh
 
-STDERR=$(dirname $1)/stderr
-if [ ! -f $STDERR ]; then
+STDERR=$(dirname "$1")/stderr
+if [ ! -f "$STDERR" ]; then
     echo "stderr file not found!"
     exit 1
 fi
 
 # Linux spelling of ERANGE
-if grep -E -q 'rtapi_app_main_fails.* Numerical result out of range' $STDERR; then
+if grep -E -q 'rtapi_app_main_fails.* Numerical result out of range' "$STDERR"; then
     echo "loadrt found the test component, and it failed to load"
     exit 0
 fi
 
 # FreeBSD spelling of ERANGE
-if grep -E -q 'rtapi_app_main_fails.* Result too large' $STDERR; then
+if grep -E -q 'rtapi_app_main_fails.* Result too large' "$STDERR"; then
     echo "loadrt found the test component, and it failed to load"
     exit 0
 fi
diff --git a/tests/module-loading/shared-test.sh b/tests/module-loading/shared-test.sh
index 4f5780138b4..79730d54d6c 100644
--- a/tests/module-loading/shared-test.sh
+++ b/tests/module-loading/shared-test.sh
@@ -3,13 +3,13 @@
 halrun setup.hal > hal-output 2>&1
 RESULT=$?
 
-NUM_PINS=$(cat hal-output | grep -E $(cat PIN_NAME_REGEX) | wc -l)
+NUM_PINS=$(grep -Ec "$(cat PIN_NAME_REGEX)" hal-output)
 
-if [ $RESULT -ne $(cat RESULT) ]; then
+if [ $RESULT -ne "$(cat RESULT)" ]; then
     exit 1
 fi
 
-if [ "$NUM_PINS" -ne $(cat NUM_PINS) ]; then
+if [ "$NUM_PINS" -ne "$(cat NUM_PINS)" ]; then
     exit 1
 fi
 
diff --git a/tests/motion/g0/test.sh b/tests/motion/g0/test.sh
index b54482c459d..ed4c5741ad3 100755
--- a/tests/motion/g0/test.sh
+++ b/tests/motion/g0/test.sh
@@ -8,14 +8,14 @@ wait_for_pin() {
     value="$2"
     maxwait=10 # seconds
     while [ 0 -lt $maxwait ] \
-      && [ "$value" != "$(halcmd -s show pin $pin | awk '{print $4}')" ]; do
+      && [ "$value" != "$(halcmd -s show pin "$pin" | awk '{print $4}')" ]; do
         sleep 1
-	maxwait=$(($maxwait -1))
+	maxwait=$((maxwait - 1))
     done
     if [ 0 -eq $maxwait ] ; then
-	echo "error: waiting for pin $pin timed out"
-	kill $linuxcncpid
-	kill $samplerpid
+	echo "E: waiting for pin $pin timed out"
+	kill "$linuxcncpid"
+	kill "$samplerpid"
 	exit 1
     fi
 }
@@ -26,49 +26,49 @@ linuxcncpid=$!
 # let linuxcnc come up
 TOGO=80
 while [  $TOGO -gt 0 ]; do
-    echo trying to connect to linuxcncrsh TOGO=$TOGO
+    echo "I: trying to connect to linuxcncrsh TOGO=$TOGO"
     if nc -z localhost 5007; then
         break
     fi
     sleep 0.25
-    TOGO=$(($TOGO - 1))
+    TOGO=$((TOGO - 1))
 done
 if [  $TOGO -eq 0 ]; then
-    echo connection to linuxcncrsh timed out
+    echo "I: connection to linuxcncrsh timed out"
     exit 1
 fi
 
 wait_for_pin motion.in-position TRUE
 
-echo starting to capture data
+echo "I: starting to capture data"
 halsampler -t >| result.halsamples &
 samplerpid=$!
 
 (
-    echo hello EMC mt 1.0
-    echo set enable EMCTOO
+    echo "hello EMC mt 1.0"
+    echo "set enable EMCTOO"
 
-    echo set estop off
-    echo set machine on
+    echo "set estop off"
+    echo "set machine on"
 
-    echo set mode mdi
+    echo "set mode mdi"
     dist=1
-    echo set mdi g0x$dist
+    echo "set mdi g0x$dist"
 
     # Wait for movement to complete
     wait_for_pin joint.0.pos-fb $dist
     wait_for_pin joint.0.in-position TRUE
     wait_for_pin joint.1.in-position TRUE
 
-    echo shutdown
+    echo "shutdown"
 ) | nc localhost 5007
 
-kill $samplerpid
-wait $samplerpid
-echo finished capturing data
+kill "$samplerpid"
+wait "$samplerpid"
+echo "I: finished capturing data"
 
 # wait for linuxcnc to finish
-wait $linuxcncpid
+wait "$linuxcncpid"
 
 exit 0
 
diff --git a/tests/overrun/checkresult b/tests/overrun/checkresult
index f398da1a04a..b64faf30722 100755
--- a/tests/overrun/checkresult
+++ b/tests/overrun/checkresult
@@ -1,5 +1,5 @@
 #!/bin/sh
 set -e
-grep -q "overrun detected in sampler" $1
-grep -q "10 overruns detected, giving up" $1
-grep -q "1 tests run, 0 successful, 1 failed . 0 expected" $1
+grep -q "overrun detected in sampler" "$1"
+grep -q "10 overruns detected, giving up" "$1"
+grep -q "1 tests run, 0 successful, 1 failed . 0 expected" "$1"
diff --git a/tests/oword/sub.0/test.sh b/tests/oword/sub.0/test.sh
index 83d69e365c8..2afa80d1ca5 100644
--- a/tests/oword/sub.0/test.sh
+++ b/tests/oword/sub.0/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/oword/while.0/test.sh b/tests/oword/while.0/test.sh
index 83d69e365c8..2afa80d1ca5 100755
--- a/tests/oword/while.0/test.sh
+++ b/tests/oword/while.0/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/remap/duplicate-o-word/test.sh b/tests/remap/duplicate-o-word/test.sh
index 13adf7d5cf6..99269de600c 100755
--- a/tests/remap/duplicate-o-word/test.sh
+++ b/tests/remap/duplicate-o-word/test.sh
@@ -1,4 +1,4 @@
 #!/bin/bash
 export INI_FILE_NAME=test.ini
-rs274 -i $INI_FILE_NAME -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+rs274 -i "$INI_FILE_NAME" -g test.ngc | awk '{$1=""; print}'
+exit "${PIPESTATUS[0]}"
diff --git a/tests/remap/fail/args.0/test.sh b/tests/remap/fail/args.0/test.sh
index 65d4d349dfe..bb2a78ea3d5 100755
--- a/tests/remap/fail/args.0/test.sh
+++ b/tests/remap/fail/args.0/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -i test.ini -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/remap/fail/args.1/test.sh b/tests/remap/fail/args.1/test.sh
index 77a112a15ca..974f6975c31 100755
--- a/tests/remap/fail/args.1/test.sh
+++ b/tests/remap/fail/args.1/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -i test.ini -n 0 -g test.ngc 2>&1
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/remap/fail/args.2/test.sh b/tests/remap/fail/args.2/test.sh
index 77a112a15ca..974f6975c31 100755
--- a/tests/remap/fail/args.2/test.sh
+++ b/tests/remap/fail/args.2/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -i test.ini -n 0 -g test.ngc 2>&1
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/remap/fail/body-ngc/test.sh b/tests/remap/fail/body-ngc/test.sh
index 77a112a15ca..974f6975c31 100755
--- a/tests/remap/fail/body-ngc/test.sh
+++ b/tests/remap/fail/body-ngc/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -i test.ini -n 0 -g test.ngc 2>&1
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/remap/m30-interaction/test.sh b/tests/remap/m30-interaction/test.sh
index 57e28aba8d2..a3af97b0369 100755
--- a/tests/remap/m30-interaction/test.sh
+++ b/tests/remap/m30-interaction/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -i test.ini -g test.ngc 2>&1 | sed 's/^ *[0-9]* //'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/remap/nested-remaps-oword/test.sh b/tests/remap/nested-remaps-oword/test.sh
index 21d662fe18f..a3af97b0369 100755
--- a/tests/remap/nested-remaps-oword/test.sh
+++ b/tests/remap/nested-remaps-oword/test.sh
@@ -1,4 +1,3 @@
 #!/bin/bash
 rs274 -i test.ini -g test.ngc 2>&1 | sed 's/^ *[0-9]* //'
-exit ${PIPESTATUS[0]}
-
+exit "${PIPESTATUS[0]}"
diff --git a/tests/remap/posargs.0/test.sh b/tests/remap/posargs.0/test.sh
index 087b90d47b6..c4f19fb4f54 100755
--- a/tests/remap/posargs.0/test.sh
+++ b/tests/remap/posargs.0/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 rs274 -i test.ini -n 0 -g test.ngc| awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/remap/remap-reentry/test.sh b/tests/remap/remap-reentry/test.sh
index 02f782fcdd5..2e101d82b63 100755
--- a/tests/remap/remap-reentry/test.sh
+++ b/tests/remap/remap-reentry/test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash -e
 rs274 -g -i test.ini test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+exit "${PIPESTATUS[0]}"
diff --git a/tests/remap/sequencing/test.sh b/tests/remap/sequencing/test.sh
index 13adf7d5cf6..99269de600c 100755
--- a/tests/remap/sequencing/test.sh
+++ b/tests/remap/sequencing/test.sh
@@ -1,4 +1,4 @@
 #!/bin/bash
 export INI_FILE_NAME=test.ini
-rs274 -i $INI_FILE_NAME -g test.ngc | awk '{$1=""; print}'
-exit ${PIPESTATUS[0]}
+rs274 -i "$INI_FILE_NAME" -g test.ngc | awk '{$1=""; print}'
+exit "${PIPESTATUS[0]}"
diff --git a/tests/rtapi_printf.0/checkresult b/tests/rtapi_printf.0/checkresult
index a5579640371..30bfaa64cae 100755
--- a/tests/rtapi_printf.0/checkresult
+++ b/tests/rtapi_printf.0/checkresult
@@ -1,2 +1,2 @@
 #!/bin/sh
-! grep -q '\*fail\*' $1
+! grep -q '\*fail\*' "$1"
diff --git a/tests/stepgen.2/checkresult b/tests/stepgen.2/checkresult
index 809e8044c40..663fd3796b8 100755
--- a/tests/stepgen.2/checkresult
+++ b/tests/stepgen.2/checkresult
@@ -1,7 +1,9 @@
 #!/bin/bash
 COUNT=0
-while read i j; do
-	if [ $j  -eq 1 ]; then COUNT=$((COUNT+1)); fi
-done < $1
+# Variable i is unused
+# shellcheck disable=SC2034
+while read -r i j; do
+	if [ "$j"  -eq 1 ]; then COUNT=$((COUNT+1)); fi
+done < "$1"
 
 test $COUNT -eq 1280
diff --git a/tests/t0/shared-test.sh b/tests/t0/shared-test.sh
index c2f4b67176b..efbea56c142 100644
--- a/tests/t0/shared-test.sh
+++ b/tests/t0/shared-test.sh
@@ -25,7 +25,7 @@ while [  $TOGO -gt 0 ]; do
         break
     fi
     sleep 0.25
-    TOGO=$(($TOGO - 1))
+    TOGO=$((TOGO - 1))
 done
 if [  $TOGO -eq 0 ]; then
     echo connection to linuxcncrsh timed out
@@ -47,12 +47,12 @@ fi
         echo 'set wait done'
     }
 
-    echo hello EMC mt 1.0
-    echo set enable EMCTOO
+    echo "hello EMC mt 1.0"
+    echo "set enable EMCTOO"
 
-    echo set estop off
-    echo set machine on
-    echo set mode mdi
+    echo "set estop off"
+    echo "set machine on"
+    echo "set mode mdi"
 
 
     #
@@ -77,12 +77,12 @@ fi
 
     # Apply the TLO of the current tool.  On both, the spindle has no tool,
     # which has 0 TLO.
-    echo set mdi g43
+    echo "set mdi g43"
     introspect 1
 
     # Apply the TLO of tool T1.  On both, T1 is a valid tool, so we use its
     # TLO.
-    echo set mdi g43 h1
+    echo "set mdi g43 h1"
     introspect 2
 
     # Apply the TLO of H0, this one is weird.
@@ -94,7 +94,7 @@ fi
     # table, this is an error and the active TLO remains unchanged (so it
     # stays as the TLO of T1 that we just set above).  If T0 is defined, we
     # apply its TLO here.
-    echo set mdi g43 h0
+    echo "set mdi g43 h0"
     introspect 3
 
 
@@ -104,18 +104,18 @@ fi
 
     # Try to change TLO of the normal tool T7.  This should work on both,
     # but not change the active TLO.
-    echo set mdi g10 l1 p7 z0.1
+    echo "set mdi g10 l1 p7 z0.1"
     introspect 4
 
     # Apply the TLO of T7, which we just tried to set.  This should work on
     # both.
-    echo set mdi g43 h7
+    echo "set mdi g43 h7"
     introspect 5
 
     # Try to change TLO of the strange tool T0.
     #
     # This should fail in every config because you cannot change T0.
-    echo set mdi g10 l1 p0 z0.2
+    echo "set mdi g10 l1 p0 z0.2"
     introspect 6
 
     # Apply the TLO of the special H0.
@@ -127,7 +127,7 @@ fi
     # table, this is an error and the active TLO remains unchanged (so it
     # stays as the TLO of T7 that we just set above).  If T0 is defined, we
     # apply its TLO here.
-    echo set mdi g43 h0
+    echo "set mdi g43 h0"
     introspect 7
 
 
@@ -136,18 +136,18 @@ fi
     #
 
     # Try to change TLO of the normal tool T7.  This should work on both.
-    echo set mdi g10 l10 p7 z0.3
+    echo "set mdi g10 l10 p7 z0.3"
     introspect 8
 
     # Apply the TLO of T7, which we just tried to set.  This should work on
     # both.
-    echo set mdi g43 h7
+    echo "set mdi g43 h7"
     introspect 9
 
     # Try to change TLO of the strange tool T0.
     #
     # This should fail on every config because you cannot change T0.
-    echo set mdi g10 l10 p0 z0.4
+    echo "set mdi g10 l10 p0 z0.4"
     introspect 10
 
     # Apply the TLO of the special H0.
@@ -159,7 +159,7 @@ fi
     # table, this is an error and the active TLO remains unchanged (so it
     # stays as the TLO of T7 that we just set above).  If T0 is defined, we
     # apply its TLO here.
-    echo set mdi g43 h0
+    echo "set mdi g43 h0"
     introspect 11
 
 
@@ -184,13 +184,13 @@ fi
     #        random with T0: -5.0 + 0.0 TLO = -5.0
     #
     # All the configs will be at Z=5.0 after switching to G59.3.
-    echo set mdi g10 l20 p9 z5
+    echo "set mdi g10 l20 p9 z5"
     introspect 11.5
 
-    echo set mdi g59.3
+    echo "set mdi g59.3"
     introspect 12
 
-    echo set mdi g54
+    echo "set mdi g54"
     introspect 13
 
     # Try to change TLO of the normal tool T7.  This should work on all
@@ -202,18 +202,18 @@ fi
     #        Random with T0: -5.0 + 0.5 = -4.5
     #
     # But these offsets are not active until the G43 below.
-    echo set mdi g10 l11 p7 z0.5
+    echo "set mdi g10 l11 p7 z0.5"
     introspect 14
 
     # Apply the TLO of T7, which we just tried to set.  This should
     # work on all configs.
-    echo set mdi g43 h7
+    echo "set mdi g43 h7"
     introspect 15
 
     # Try to change TLO of the strange tool T0.
     #
     # This should fail on every config because you cannot change T0.
-    echo set mdi g10 l11 p0 z0.6
+    echo "set mdi g10 l11 p0 z0.6"
     introspect 16
 
     # Apply the TLO of the special H0.
@@ -225,7 +225,7 @@ fi
     # table, this is an error and the active TLO remains unchanged (so it
     # stays as the TLO of T7 that we just set above).  If T0 is defined, we
     # apply its TLO here.
-    echo set mdi g43 h0
+    echo "set mdi g43 h0"
     introspect 17
 
 
@@ -242,7 +242,7 @@ fi
 
     # Switch to the valid tool T50 but don't apply its TLO yet.
     # This should work on all configs.
-    echo set mdi t50 m6
+    echo "set mdi t50 m6"
     introspect 100
 
 
@@ -252,17 +252,17 @@ fi
 
     # Apply the TLO of the current tool.  On all configs, the spindle has
     # T50.  This should work on all configs.
-    echo set mdi g43
+    echo "set mdi g43"
     introspect 101
 
     # change the TLO of the normal tool T7
     # this should work on both, but not change the active TLO
-    echo set mdi g10 l10 p7 z1.1
+    echo "set mdi g10 l10 p7 z1.1"
     introspect 102
 
     # apply the TLO of the normal tool T7 (TLO of 0.5 set above)
     # this should work on both
-    echo set mdi g43 h7
+    echo "set mdi g43 h7"
     introspect 103
 
     # try to change the TLO of T0
@@ -272,7 +272,7 @@ fi
     # On random without T0 this should fail because there is no T0.
     #
     # On random with T0 this should fail because you can't change T0.
-    echo set mdi g10 l10 p0 z1.2
+    echo "set mdi g10 l10 p0 z1.2"
     introspect 104
 
     # Apply the TLO of the special H0.
@@ -284,7 +284,7 @@ fi
     # table, this is an error and the active TLO remains unchanged (so it
     # stays as the TLO of T7 that we just set above).  If T0 is defined, we
     # apply its TLO here.
-    echo set mdi g43 h0
+    echo "set mdi g43 h0"
     introspect 105
 
 
@@ -294,12 +294,12 @@ fi
 
     # Try to change TLO of the normal tool T7.  This should work on all
     # configs, but not change the active TLO.
-    echo set mdi g10 l1 p7 z1.3
+    echo "set mdi g10 l1 p7 z1.3"
     introspect 106
 
     # Apply the TLO of T7, which we just tried to set.  This should work on
     # all configs.
-    echo set mdi g43 h7
+    echo "set mdi g43 h7"
     introspect 107
 
     # Try to change TLO of the strange tool T0.
@@ -309,7 +309,7 @@ fi
     # It should fail on random without T0 because it has no T0.
     #
     # It should fail on random with T0 because you cannot change T0.
-    echo set mdi g10 l1 p0 z1.4
+    echo "set mdi g10 l1 p0 z1.4"
     introspect 108
 
     # Apply the TLO of the special H0.
@@ -321,7 +321,7 @@ fi
     # from T7 above.
     #
     # It should work on random with T0 and give us the TLO of T0 (0.0).
-    echo set mdi g43 h0
+    echo "set mdi g43 h0"
     introspect 109
 
 
@@ -331,12 +331,12 @@ fi
 
     # Try to change TLO of the normal tool T7.  This should work on all
     # configs.
-    echo set mdi g10 l10 p7 z1.5
+    echo "set mdi g10 l10 p7 z1.5"
     introspect 110
 
     # Apply the TLO of T7, which we just tried to set.  This should work on
     # all configs.
-    echo set mdi g43 h7
+    echo "set mdi g43 h7"
     introspect 111
 
     # Try to change TLO of the strange tool T0.
@@ -346,7 +346,7 @@ fi
     # It should fail on random without T0 because it has no T0.
     #
     # It should fail on random with T0 because you cannot change T0
-    echo set mdi g10 l10 p0 z1.6
+    echo "set mdi g10 l10 p0 z1.6"
     introspect 112
 
     # Apply the TLO of the special H0.
@@ -358,12 +358,12 @@ fi
     # from T7 above.
     #
     # It should work on random with T0 and give us the TLO of T0 (0.0).
-    echo set mdi g43 h0
+    echo "set mdi g43 h0"
     introspect 113
 
     # Try to change TLO of the currently loaded tool, T50.
     # This should work on all configs but not change the active TLO
-    echo set mdi g10 l10 p50 z1.7
+    echo "set mdi g10 l10 p50 z1.7"
     introspect 114
 
     # Apply the TLO of the special H0.
@@ -375,17 +375,17 @@ fi
     # from T7 above.
     #
     # It should work on random with T0 and give us the TLO of T0 (0.0).
-    echo set mdi g43 h0
+    echo "set mdi g43 h0"
     introspect 115
 
     # Apply the TLO of T7.
     # This should work on all configs.
-    echo set mdi g43 h7
+    echo "set mdi g43 h7"
     introspect 116
 
     # Apply the TLO of the current tool
     # This should work on all configs.
-    echo set mdi g43
+    echo "set mdi g43"
     introspect 117
 
 
@@ -405,23 +405,23 @@ fi
     #     -6.0 + 1.7 TLO = -4.3
     #
     # All the configs will be at Z = 6.0 after switching to G59.3.
-    echo set mdi g10 l20 p9 z6
+    echo "set mdi g10 l20 p9 z6"
     introspect 117.5
 
-    echo set mdi g59.3
+    echo "set mdi g59.3"
     introspect 118
 
-    echo set mdi g54
+    echo "set mdi g54"
     introspect 119
 
     # Try to change TLO of the normal tool T7.  This should work on all
     # configs.
-    echo set mdi g10 l11 p7 z1.8
+    echo "set mdi g10 l11 p7 z1.8"
     introspect 120
 
     # Apply the TLO of T7, which we just tried to set.  This should
     # work on all configs.
-    echo set mdi g43 h7
+    echo "set mdi g43 h7"
     introspect 121
 
     # Try to change TLO of the strange tool T0.
@@ -431,7 +431,7 @@ fi
     # It should fail on random without T0 because it has no T0.
     #
     # This should fail on random with T0 because you cannot change T0.
-    echo set mdi g10 l11 p0 z1.3
+    echo "set mdi g10 l11 p0 z1.3"
     introspect 122
 
     # Apply the TLO of T0, which we just tried to set.
@@ -443,7 +443,7 @@ fi
     # above.
     #
     # It should work on random with T0 and give us the TLO of T0: 0.0
-    echo set mdi g43 h0
+    echo "set mdi g43 h0"
     introspect 123
 
 
@@ -461,7 +461,7 @@ fi
     #
     # On random with T0 this should work and put T0 in the spindle.
 
-    echo set mdi t0 m6
+    echo "set mdi t0 m6"
     introspect 200
 
 
@@ -477,17 +477,17 @@ fi
     # set above.
     #
     # On random with T0 the spindle has tool T0, which has a 0 TLO.
-    echo set mdi g43
+    echo "set mdi g43"
     introspect 201
 
     # change the TLO of the normal tool T7
     # this should work on all configs, but not change the active TLO
-    echo set mdi g10 l10 p7 z2.0
+    echo "set mdi g10 l10 p7 z2.0"
     introspect 202
 
     # apply the TLO of the normal tool T7 (TLO set above)
     # this should work on all configs
-    echo set mdi g43 h7
+    echo "set mdi g43 h7"
     introspect 203
 
     # try to change the TLO of T0
@@ -497,7 +497,7 @@ fi
     # On random without T0 this should fail because there is no T0.
     #
     # On random with T0 this should fail because you can't change T0.
-    echo set mdi g10 l10 p0 z2.1
+    echo "set mdi g10 l10 p0 z2.1"
     introspect 204
 
     # try to apply the TLO of H0
@@ -510,7 +510,7 @@ fi
     # unchanged.
     #
     # On random with T0 this should apply the TLO of T0 (0.0).
-    echo set mdi g43 h0
+    echo "set mdi g43 h0"
     introspect 205
 
 
@@ -520,12 +520,12 @@ fi
 
     # Try to change TLO of the normal tool T7.  This should work on all
     # configs, but not change the active TLO.
-    echo set mdi g10 l1 p7 z2.2
+    echo "set mdi g10 l1 p7 z2.2"
     introspect 206
 
     # Apply the TLO of T7, which we just tried to set.  This should work on
     # all configs.
-    echo set mdi g43 h7
+    echo "set mdi g43 h7"
     introspect 207
 
     # Try to change TLO of the strange tool T0.
@@ -535,7 +535,7 @@ fi
     # It should fail on random without T0 because it has no T0.
     #
     # This should fail on random with T0 because you cannot change T0.
-    echo set mdi g10 l1 p0 z2.3
+    echo "set mdi g10 l1 p0 z2.3"
     introspect 208
 
     # Apply the TLO of H0.
@@ -547,7 +547,7 @@ fi
     # from T7 above.
     #
     # It should work on random with TLO and give us the TLO of T0.
-    echo set mdi g43 h0
+    echo "set mdi g43 h0"
     introspect 209
 
 
@@ -557,12 +557,12 @@ fi
 
     # Try to change TLO of the normal tool T7.  This should work on all
     # configs.
-    echo set mdi g10 l10 p7 z2.4
+    echo "set mdi g10 l10 p7 z2.4"
     introspect 210
 
     # Apply the TLO of T7, which we just tried to set.  This should work on
     # all configs.
-    echo set mdi g43 h7
+    echo "set mdi g43 h7"
     introspect 211
 
     # Try to change TLO of the strange tool T0.
@@ -572,7 +572,7 @@ fi
     # It should fail on random without T0 because it has no T0.
     #
     # It should fail on random with T0 because you cannot change T0
-    echo set mdi g10 l10 p0 z2.5
+    echo "set mdi g10 l10 p0 z2.5"
     introspect 212
 
     # Apply the TLO of the special H0.
@@ -584,7 +584,7 @@ fi
     # from T7 above.
     #
     # It should work on random with T0 and give us the TLO of T0 (0.0).
-    echo set mdi g43 h0
+    echo "set mdi g43 h0"
     introspect 213
 
 
@@ -609,13 +609,13 @@ fi
     #        random with T0: -7.0 + 0.0 TLO = -7.0
     #
     # All the configs will be at Z=7.0 after switching to G59.3.
-    echo set mdi g10 l20 p9 z7
+    echo "set mdi g10 l20 p9 z7"
     introspect 213.5
 
-    echo set mdi g59.3
+    echo "set mdi g59.3"
     introspect 214
 
-    echo set mdi g54
+    echo "set mdi g54"
     introspect 215
 
     # Try to change TLO of the normal tool T7.  This should work on all
@@ -627,12 +627,12 @@ fi
     #        Random with T0: -7.0 + 2.6 = -4.4
     #
     # But these offsets are not active until the G43 below.
-    echo set mdi g10 l11 p7 z2.6
+    echo "set mdi g10 l11 p7 z2.6"
     introspect 216
 
     # Apply the TLO of T7, which we just tried to set.  This should
     # work on all configs.
-    echo set mdi g43 h7
+    echo "set mdi g43 h7"
     introspect 217
 
     # Try to change TLO of the strange tool T0.
@@ -642,7 +642,7 @@ fi
     # It should fail on random without T0 because it has no T0.
     #
     # It should work on random with T0 because you cannot change T0.
-    echo set mdi g10 l11 p0 z2.7
+    echo "set mdi g10 l11 p0 z2.7"
     introspect 218
 
     # Apply the TLO of H0.
@@ -655,7 +655,7 @@ fi
     #
     # It should work on random with T0 and give us a TLO of the tool in the
     # spindle, T0
-    echo set mdi g43 h0
+    echo "set mdi g43 h0"
     introspect 219
 
 
diff --git a/tests/t0/subs/M100 b/tests/t0/subs/M100
index b32c2433438..d64a15ab176 100755
--- a/tests/t0/subs/M100
+++ b/tests/t0/subs/M100
@@ -15,15 +15,15 @@ Q=$2
 #echo Q is $Q >> $OUT_FILE
 
 case $P in
-    0.000000) echo "X = $Q" >> $OUT_FILE;;
-    1.000000) echo "Y = $Q" >> $OUT_FILE;;
-    2.000000) echo "Z = $Q" >> $OUT_FILE;;
-    3.000000) echo "toolno = $Q" >> $OUT_FILE;;
-    4.000000) echo "tlo_z = $Q" >> $OUT_FILE;;
-    5.000000) echo "" >> $OUT_FILE;;
-    6.000000) echo "sequence number $Q" >> $OUT_FILE;;
+    0.000000) echo "X = $Q" >> "$OUT_FILE" ;;
+    1.000000) echo "Y = $Q" >> "$OUT_FILE" ;;
+    2.000000) echo "Z = $Q" >> "$OUT_FILE" ;;
+    3.000000) echo "toolno = $Q" >> "$OUT_FILE" ;;
+    4.000000) echo "tlo_z = $Q" >> "$OUT_FILE" ;;
+    5.000000) echo "" >> "$OUT_FILE" ;;
+    6.000000) echo "sequence number $Q" >> "$OUT_FILE" ;;
     *)
-        echo "unknown P=$P (Q=$Q)" >> $OUT_FILE
+        echo "unknown P=$P (Q=$Q)" >> "$OUT_FILE"
         exit 1;;
 esac
 
diff --git a/tests/toolchanger/subs/M100 b/tests/toolchanger/subs/M100
index b32c2433438..d64a15ab176 100755
--- a/tests/toolchanger/subs/M100
+++ b/tests/toolchanger/subs/M100
@@ -15,15 +15,15 @@ Q=$2
 #echo Q is $Q >> $OUT_FILE
 
 case $P in
-    0.000000) echo "X = $Q" >> $OUT_FILE;;
-    1.000000) echo "Y = $Q" >> $OUT_FILE;;
-    2.000000) echo "Z = $Q" >> $OUT_FILE;;
-    3.000000) echo "toolno = $Q" >> $OUT_FILE;;
-    4.000000) echo "tlo_z = $Q" >> $OUT_FILE;;
-    5.000000) echo "" >> $OUT_FILE;;
-    6.000000) echo "sequence number $Q" >> $OUT_FILE;;
+    0.000000) echo "X = $Q" >> "$OUT_FILE" ;;
+    1.000000) echo "Y = $Q" >> "$OUT_FILE" ;;
+    2.000000) echo "Z = $Q" >> "$OUT_FILE" ;;
+    3.000000) echo "toolno = $Q" >> "$OUT_FILE" ;;
+    4.000000) echo "tlo_z = $Q" >> "$OUT_FILE" ;;
+    5.000000) echo "" >> "$OUT_FILE" ;;
+    6.000000) echo "sequence number $Q" >> "$OUT_FILE" ;;
     *)
-        echo "unknown P=$P (Q=$Q)" >> $OUT_FILE
+        echo "unknown P=$P (Q=$Q)" >> "$OUT_FILE"
         exit 1;;
 esac
 
diff --git a/tests/toolchanger/toolno-pocket-differ/shared-test.sh b/tests/toolchanger/toolno-pocket-differ/shared-test.sh
index 34426e36e4c..e0533206ae3 100755
--- a/tests/toolchanger/toolno-pocket-differ/shared-test.sh
+++ b/tests/toolchanger/toolno-pocket-differ/shared-test.sh
@@ -10,7 +10,7 @@ cp ../../simpockets.tbl.original simpockets.tbl
 rm -f gcode-output
 
 if nc -z localhost 5007; then
-    echo "Process already listening on port 5007. Exiting"
+    echo "E: Process already listening on port 5007. Exiting"
     exit 1
 fi
 
@@ -20,15 +20,15 @@ linuxcnc -r sim.ini &
 # let linuxcnc come up
 TOGO=80
 while [  $TOGO -gt 0 ]; do
-    echo trying to connect to linuxcncrsh TOGO=$TOGO
+    echo "I: trying to connect to linuxcncrsh TOGO=$TOGO"
     if nc -z localhost 5007; then
         break
     fi
     sleep 0.25
-    TOGO=$(($TOGO - 1))
+    TOGO=$((TOGO - 1))
 done
 if [  $TOGO -eq 0 ]; then
-    echo connection to linuxcncrsh timed out
+    echo "I: connection to linuxcncrsh timed out"
     exit 1
 fi
 
@@ -37,123 +37,123 @@ fi
     function introspect() {
         SEQUENCE_NUMBER=$1
         echo "set mdi m100 P6 Q$SEQUENCE_NUMBER"  # sequence number
-        echo 'set mdi m100 P0 Q#5420'             # X
-        echo 'set mdi m100 P1 Q#5421'             # Y
-        echo 'set mdi m100 P2 Q#5422'             # Z
-        echo 'set mdi m100 P3 Q#5400'             # toolno
-        echo 'set mdi m100 P4 Q#5403'             # TLO z
-        echo 'set mdi m100 P5'                    # blank line
+        echo "set mdi m100 P0 Q#5420"             # X
+        echo "set mdi m100 P1 Q#5421"             # Y
+        echo "set mdi m100 P2 Q#5422"             # Z
+        echo "set mdi m100 P3 Q#5400"             # toolno
+        echo "set mdi m100 P4 Q#5403"             # TLO z
+        echo "set mdi m100 P5"                    # blank line
     }
 
-    echo hello EMC mt 1.0
-    echo set enable EMCTOO
+    echo "hello EMC mt 1.0"
+    echo "set enable EMCTOO"
 
-    echo set estop off
-    echo set machine on
-    echo set mode mdi
+    echo "set estop off"
+    echo "set machine on"
+    echo "set mode mdi"
 
     introspect 0
 
-    echo set mdi t1 m6
+    echo "set mdi t1 m6"
     introspect 1
 
-    echo set mdi g43
+    echo "set mdi g43"
     introspect 2
 
-    echo set mdi g10 l10 p1 z.1
+    echo "set mdi g10 l10 p1 z.1"
     introspect 3
 
-    echo set mdi g43
+    echo "set mdi g43"
     introspect 4
 
-    echo set mdi g10 l10 p10 z.15
+    echo "set mdi g10 l10 p10 z.15"
     introspect 5
 
-    echo set mdi g43
+    echo "set mdi g43"
     introspect 6
 
-    echo set mdi g10 l10 p99999 z.2
+    echo "set mdi g10 l10 p99999 z.2"
     introspect 7
 
-    echo set mdi g43
+    echo "set mdi g43"
     introspect 8
 
 
-    echo set mdi t10 m6
+    echo "set mdi t10 m6"
     introspect 9
 
-    echo set mdi g43
+    echo "set mdi g43"
     introspect 10
 
-    echo set mdi g10 l10 p1 z.103
+    echo "set mdi g10 l10 p1 z.103"
     introspect 11
 
-    echo set mdi g43
+    echo "set mdi g43"
     introspect 12
 
-    echo set mdi g10 l10 p10 z.1035
+    echo "set mdi g10 l10 p10 z.1035"
     introspect 13
 
-    echo set mdi g43
+    echo "set mdi g43"
     introspect 14
 
-    echo set mdi g10 l10 p99999 z.104
+    echo "set mdi g10 l10 p99999 z.104"
     introspect 15
 
-    echo set mdi g43
+    echo "set mdi g43"
     introspect 16
 
 
-    echo set mdi t99999 m6
+    echo "set mdi t99999 m6"
     introspect 17
 
-    echo set mdi g43
+    echo "set mdi g43"
     introspect 18
 
-    echo set mdi g10 l10 p1 z.3
+    echo "set mdi g10 l10 p1 z.3"
     introspect 19
 
-    echo set mdi g43
+    echo "set mdi g43"
     introspect 20
 
-    echo set mdi g10 l10 p10 z.35
+    echo "set mdi g10 l10 p10 z.35"
     introspect 21
 
-    echo set mdi g43
+    echo "set mdi g43"
     introspect 22
 
-    echo set mdi g10 l10 p99999 z.4
+    echo "set mdi g10 l10 p99999 z.4"
     introspect 23
 
-    echo set mdi g43
+    echo "set mdi g43"
     introspect 24
 
 
-    echo set mdi t1 m6
+    echo "set mdi t1 m6"
     introspect 25
 
-    echo set mdi g43
+    echo "set mdi g43"
     introspect 26
 
 
-    echo set mdi t10 m6
+    echo "set mdi t10 m6"
     introspect 27
 
-    echo set mdi g43
+    echo "set mdi g43"
     introspect 28
 
 
-    echo set mdi t99999 m6
+    echo "set mdi t99999 m6"
     introspect 29
 
-    echo set mdi g43
+    echo "set mdi g43"
     introspect 30
 
 
     # wait for linuxcnc to finish
-    echo set wait done
+    echo "set wait done"
 
-    echo shutdown
+    echo "shutdown"
 ) | nc localhost 5007
 
 
diff --git a/tests/trajectory-planner/circular-arcs/test-lengths.sh b/tests/trajectory-planner/circular-arcs/test-lengths.sh
index 893f1e01baa..7611afd25d8 100755
--- a/tests/trajectory-planner/circular-arcs/test-lengths.sh
+++ b/tests/trajectory-planner/circular-arcs/test-lengths.sh
@@ -2,8 +2,8 @@
 set -o monitor
 ./build-debug.sh
 cp position.blank position.txt
-linuxcnc $1 > test.log &
-./machine_setup.py $2
+linuxcnc "$1" > test.log &
+./machine_setup.py "$2"
 fg
 ./save_lengths.sh test.log
 #if [ -a length_data.log ] 
diff --git a/tests/trajectory-planner/circular-arcs/util/save_vel.sh b/tests/trajectory-planner/circular-arcs/util/save_vel.sh
index 16d43718ee5..c0fc792c545 100755
--- a/tests/trajectory-planner/circular-arcs/util/save_vel.sh
+++ b/tests/trajectory-planner/circular-arcs/util/save_vel.sh
@@ -1,7 +1,7 @@
 #!/bin/bash
 set -o nounset                              # Treat unset variables as an error
 
-if [ -a $1 ] 
+if [ -a "$1" ]
 then
-    awk '/tc state/ {print $5,$8,$11}' $1 > vel_data.log
+    awk '/tc state/ {print $5,$8,$11}' "$1" > vel_data.log
 fi