shellcheck: fix usse -n instead of ! -z (SC2236 SC2237)

- https://www.shellcheck.net/wiki/SC2236 -- Use -n instead of ! -z.
 - https://www.shellcheck.net/wiki/SC2237 -- Use [ -n .. ] instead of ! [ -z ....

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

utils/filtron.sh

@@ -97,7 +97,7 @@ If needed, set PUBLIC_URL of your WEB service in the '${DOT_CONFIG#"$REPO_ROOT/"
   FILTRON_TARGET : ${FILTRON_TARGET}
 
 EOF
-    [ ! -z "${1+x}" ] &&  err_msg "$1"
+    [[ -n ${1} ]] &&  err_msg "$1"
 }
 
 main() {

utils/lib.sh

@@ -57,7 +57,7 @@ required_commands() {
     # usage:  requires_commands [cmd1 ...]
 
     local exit_val=0
-    while [ ! -z "$1" ]; do
+    while [ -n "$1" ]; do
 
         if ! command -v "$1" &>/dev/null; then
             err_msg "missing command $1"
@@ -125,7 +125,7 @@ rst_title() {
 rst_para() {
     # usage:  RST_INDENT=1 rst_para "lorem ipsum ..."
     local prefix=''
-    if ! [[ -z $RST_INDENT ]] && [[ $RST_INDENT -gt 0 ]]; then
+    if [[ -n $RST_INDENT ]] && [[ $RST_INDENT -gt 0 ]]; then
         prefix="$(for i in $(seq 1 "$RST_INDENT"); do printf "  "; done)"
         echo -en "\n$*\n" | $FMT | prefix_stdout "$prefix"
     else
@@ -151,8 +151,8 @@ wait_key(){
     local msg="${MSG}"
     [[ -z "$msg" ]] && msg="${_Green}** press any [${_BCyan}KEY${_Green}] to continue **${_creset}"
 
-    [[ ! -z $FORCE_TIMEOUT ]] && _t=$FORCE_TIMEOUT
-    [[ ! -z $_t ]] && _t="-t $_t"
+    [[ -n $FORCE_TIMEOUT ]] && _t=$FORCE_TIMEOUT
+    [[ -n $_t ]] && _t="-t $_t"
     printf "$msg"
     # shellcheck disable=SC2086
     read -r -s -n1 $_t
@@ -167,8 +167,8 @@ ask_yn() {
     local EXIT_NO=1  # exit status 1 --> error code
 
     local _t=$3
-    [[ ! -z $FORCE_TIMEOUT ]] && _t=$FORCE_TIMEOUT
-    [[ ! -z $_t ]] && _t="-t $_t"
+    [[ -n $FORCE_TIMEOUT ]] && _t=$FORCE_TIMEOUT
+    [[ -n $_t ]] && _t="-t $_t"
     case "${FORCE_SELECTION:-${2}}" in
         Y) return ${EXIT_YES} ;;
         N) return ${EXIT_NO} ;;
@@ -218,7 +218,7 @@ tee_stderr () {
     #    hello
 
     local _t="0";
-    if [[ ! -z $1 ]] ; then _t="$1"; fi
+    if [[ -n $1 ]] ; then _t="$1"; fi
 
     (while read -r line; do
          # shellcheck disable=SC2086
@@ -233,7 +233,7 @@ prefix_stdout () {
 
     local prefix="${_BYellow}-->|${_creset}"
 
-    if [[ ! -z $1 ]] ; then prefix="${_BYellow}$1${_creset}"; fi
+    if [[ -n $1 ]] ; then prefix="${_BYellow}$1${_creset}"; fi
 
     # shellcheck disable=SC2162
     (while IFS= read line; do
@@ -260,7 +260,7 @@ cache_download() {
 
     local exit_value=0
 
-    if [[ ! -z ${SUDO_USER} ]]; then
+    if [[ -n ${SUDO_USER} ]]; then
         sudo -u "${SUDO_USER}" mkdir -p "${CACHE}"
     else
         mkdir -p "${CACHE}"
@@ -274,7 +274,7 @@ cache_download() {
     if [[ ! -f "${CACHE}/$2" ]]; then
         info_msg "caching: $1"
         info_msg "  --> ${CACHE}/$2"
-        if [[ ! -z ${SUDO_USER} ]]; then
+        if [[ -n ${SUDO_USER} ]]; then
             sudo -u "${SUDO_USER}" wget --progress=bar -O "${CACHE}/$2" "$1" ; exit_value=$?
         else
             wget --progress=bar -O "${CACHE}/$2" "$1" ; exit_value=$?
@@ -298,8 +298,8 @@ choose_one() {
     local choice=$1;
     local max="${#@}"
     local _t
-    [[ ! -z $FORCE_TIMEOUT ]] && _t=$FORCE_TIMEOUT
-    [[ ! -z $_t ]] && _t="-t $_t"
+    [[ -n $FORCE_TIMEOUT ]] && _t=$FORCE_TIMEOUT
+    [[ -n $_t ]] && _t="-t $_t"
 
     list=("$@")
     echo -e "${_BGreen}Menu::${_creset}"
@@ -374,7 +374,7 @@ install_template() {
     local chmod="${pos_args[4]-644}"
 
     info_msg "install (eval=$do_eval): ${dst}"
-    [[ ! -z $variant ]] && info_msg "variant: ${variant}"
+    [[ -n $variant ]] && info_msg "variant: ${variant}"
 
     if [[ ! -f "${template_origin}" ]] ; then
         err_msg "${template_origin} does not exists"
@@ -386,14 +386,14 @@ install_template() {
     if [[ "$do_eval" == "1" ]]; then
         template_file="${CACHE}${dst}${variant}"
         info_msg "BUILD template ${template_file}"
-        if [[ ! -z ${SUDO_USER} ]]; then
+        if [[ -n ${SUDO_USER} ]]; then
             sudo -u "${SUDO_USER}" mkdir -p "$(dirname "${template_file}")"
         else
             mkdir -p "$(dirname "${template_file}")"
         fi
         # shellcheck disable=SC2086
         eval "echo \"$(cat ${template_origin})\"" > "${template_file}"
-        if [[ ! -z ${SUDO_USER} ]]; then
+        if [[ -n ${SUDO_USER} ]]; then
             chown "${SUDO_USER}:${SUDO_USER}" "${template_file}"
         fi
     else
@@ -856,8 +856,8 @@ git_clone() {
     fi
 
     [[ -z $branch ]] && branch=master
-    [[ -z $user ]] && [[ ! -z "${SUDO_USER}" ]] && user="${SUDO_USER}"
-    [[ ! -z $user ]] && bash_cmd="sudo -H -u $user -i"
+    [[ -z $user ]] && [[ -n "${SUDO_USER}" ]] && user="${SUDO_USER}"
+    [[ -n $user ]] && bash_cmd="sudo -H -u $user -i"
 
     if [[ -d "${dest}" ]] ; then
         info_msg "already cloned: $dest"

utils/lxc.sh

@@ -31,6 +31,7 @@ ubu1804_boilerplate="
 export DEBIAN_FRONTEND=noninteractive
 apt-get install -y git curl wget
 "
+# shellcheck disable=SC2034
 ubu1904_boilerplate="$ubu1804_boilerplate"
 
 REMOTE_IMAGES=()
@@ -75,7 +76,7 @@ all LXC containers:
   ${LOCAL_IMAGES[@]}
 
 EOF
-    [ ! -z "${1+x}" ] &&  err_msg "$1"
+    [ -n "${1+x}" ] &&  err_msg "$1"
 }
 
 lxd_info() {
@@ -255,7 +256,7 @@ lxc_boilerplate_containers() {
         lxc start -q "${HOST_PREFIX}-${shortname}" &>/dev/null
         boilerplate_script="${shortname}_boilerplate"
         boilerplate_script="${!boilerplate_script}"
-        if [[ ! -z "${boilerplate_script}" ]]; then
+        if [[ -n "${boilerplate_script}" ]]; then
             echo "$boilerplate_script" \
                 | lxc exec "${HOST_PREFIX}-${shortname}" -- bash \
                 | prefix_stdout " ${HOST_PREFIX}-${shortname} | "
@@ -305,11 +306,13 @@ add_subordinate_ids() {
 
 del_subordinate_ids() {
     local out
+    local exit_value
     if  grep "root:${HOST_USER_ID}:1" /etc/subuid -qs; then
         # TODO: root user is always in use by process 1, how can we remove subordinates?
         info_msg "remove lxd permission to map ${HOST_USER_ID}'s user/group id through"
         out=$(usermod --del-subuids "${HOST_USER_ID}-${HOST_USER_ID}" --del-subgids "${HOST_GROUP_ID}-${HOST_GROUP_ID}" root 2>&1)
-        if [ ! -z $? ]; then
+        exit_val=$?
+        if [ $exit_val -ne 0 ]; then
             err_msg "$out"
         fi
     else

utils/morty.sh

@@ -84,7 +84,7 @@ ${DOT_CONFIG#"$REPO_ROOT/"} file::
   SERVICE_USER :   ${SERVICE_USER}
 EOF
     info_searx
-    [ ! -z "${1+x}" ] &&  err_msg "$1"
+    [[ -n ${1} ]] &&  err_msg "$1"
 }
 
 info_searx() {

utils/searx.sh

@@ -110,7 +110,7 @@ If needed, set PUBLIC_URL of your WEB service in the '${DOT_CONFIG#"$REPO_ROOT/"
   SERVICE_USER        : ${SERVICE_USER}
 
 EOF
-    [ ! -z "${1+x}" ] &&  err_msg "$1"
+    [[ -n ${1} ]] &&  err_msg "$1"
 }
 
 main() {