Adding linting for initcpio scripts

archiso/initcpio/install/*:
Setting bash shebang for all scripts and making them comform with shellcheck.

archiso/initcpio/{hooks,script}/*:
Setting ash shebang for all scripts and making them comform with shellcheck (for dash, as shellcheck has no ash specific
ruleset). Essentially the ash based scripts should be POSIX compliant as much as possible to have an easier time
writing, debugging and maintaining them.
Ensuring that variables are not treated as options and introducing variable quoting.

.gitlab-ci.yml:
Integrating shellcheck for initcpio scripts.

Closes #32

17 files changed, 188 insertions, 156 deletions

diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index ab2f51e..74ecdd3 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -15,3 +15,7 @@ lint:
         configs/releng/airootfs/root/.automated_script.sh
         configs/releng/airootfs/usr/local/bin/choose-mirror
         scripts/run_archiso.sh
+        archiso/initcpio/install/*
+    - shellcheck -s dash
+        archiso/initcpio/hooks/*
+        archiso/initcpio/script/*
diff --git a/archiso/initcpio/hooks/archiso b/archiso/initcpio/hooks/archiso
index 5c56561..44abb88 100644
--- a/archiso/initcpio/hooks/archiso
+++ b/archiso/initcpio/hooks/archiso
@@ -1,3 +1,5 @@
+#!/bin/ash
+
 # args: source, newroot, mountpoint
 _mnt_dmsnapshot() {
     local img="${1}"
@@ -8,19 +10,19 @@ _mnt_dmsnapshot() {
     local dm_snap_name="${dm_snap_prefix}_${img_name}"
     local ro_dev ro_dev_size rw_dev
 
-    ro_dev=$(losetup --find --show --read-only "${img}")
-    echo ${ro_dev} >> /run/archiso/used_block_devices
-    ro_dev_size=$(blockdev --getsz ${ro_dev})
+    ro_dev="$(losetup --find --show --read-only -- "${img}")"
+    echo "${ro_dev}" >> /run/archiso/used_block_devices
+    ro_dev_size="$(blockdev --getsz -- "${ro_dev}")"
 
-    if [[ "${cow_persistent}" == "P" ]]; then
-        if [[ -f "/run/archiso/cowspace/${cow_directory}/${img_name}.cow" ]]; then
+    if [ "${cow_persistent}" = "P" ]; then
+        if [ -f "/run/archiso/cowspace/${cow_directory}/${img_name}.cow" ]; then
             msg ":: Found '/run/archiso/cowspace/${cow_directory}/${img_name}.cow', using as persistent."
         else
             msg ":: Creating '/run/archiso/cowspace/${cow_directory}/${img_name}.cow' as persistent."
             truncate -s "${cow_spacesize}" "/run/archiso/cowspace/${cow_directory}/${img_name}.cow"
         fi
     else
-        if [[ -f "/run/archiso/cowspace/${cow_directory}/${img_name}.cow" ]]; then
+        if [ -f "/run/archiso/cowspace/${cow_directory}/${img_name}.cow" ]; then
             msg ":: Found '/run/archiso/cowspace/${cow_directory}/${img_name}.cow' but non-persistent requested, removing."
             rm -f "/run/archiso/cowspace/${cow_directory}/${img_name}.cow"
         fi
@@ -28,17 +30,18 @@ _mnt_dmsnapshot() {
         truncate -s "${cow_spacesize}" "/run/archiso/cowspace/${cow_directory}/${img_name}.cow"
     fi
 
-    rw_dev=$(losetup --find --show "/run/archiso/cowspace/${cow_directory}/${img_name}.cow")
-    echo ${rw_dev} >> /run/archiso/used_block_devices
+    rw_dev="$(losetup --find --show "/run/archiso/cowspace/${cow_directory}/${img_name}.cow")"
+    echo "${rw_dev}" >> /run/archiso/used_block_devices
 
-    dmsetup create ${dm_snap_name} --table "0 ${ro_dev_size} snapshot ${ro_dev} ${rw_dev} ${cow_persistent} ${cow_chunksize}"
+    dmsetup create "${dm_snap_name}" --table \
+        "0 ${ro_dev_size} snapshot ${ro_dev} ${rw_dev} ${cow_persistent} ${cow_chunksize}"
 
-    if [[ "${cow_persistent}" != "P" ]]; then
+    if [ "${cow_persistent}" != "P" ]; then
         rm -f "/run/archiso/cowspace/${cow_directory}/${img_name}.cow"
     fi
 
     _mnt_dev "/dev/mapper/${dm_snap_name}" "${newroot}${mnt}" "-w" "defaults"
-    echo $(readlink -f /dev/mapper/${dm_snap_name}) >> /run/archiso/used_block_devices
+    readlink -f "/dev/mapper/${dm_snap_name}" >> /run/archiso/used_block_devices
 }
 
 # args: source, newroot, mountpoint
@@ -46,8 +49,10 @@ _mnt_overlayfs() {
     local src="${1}"
     local newroot="${2}"
     local mnt="${3}"
-    mkdir -p /run/archiso/cowspace/${cow_directory}/upperdir /run/archiso/cowspace/${cow_directory}/workdir
-    mount -t overlay -o lowerdir=${src},upperdir=/run/archiso/cowspace/${cow_directory}/upperdir,workdir=/run/archiso/cowspace/${cow_directory}/workdir airootfs "${newroot}${mnt}"
+    mkdir -p "/run/archiso/cowspace/${cow_directory}/upperdir" "/run/archiso/cowspace/${cow_directory}/workdir"
+    mount -t overlay -o \
+    "lowerdir=${src},upperdir=/run/archiso/cowspace/${cow_directory}/upperdir,workdir=/run/archiso/cowspace/${cow_directory}/workdir" \
+    airootfs "${newroot}${mnt}"
 }
 
 
@@ -58,17 +63,18 @@ _mnt_sfs() {
     local img_fullname="${img##*/}"
     local sfs_dev
 
-    if [[ "${copytoram}" == "y" ]]; then
+    # shellcheck disable=SC2154 # defined via initcpio's parse_cmdline()
+    if [ "${copytoram}" = "y" ]; then
         msg -n ":: Copying squashfs image to RAM..."
-        if ! cp "${img}" "/run/archiso/copytoram/${img_fullname}" ; then
+        if ! cp -- "${img}" "/run/archiso/copytoram/${img_fullname}" ; then
             echo "ERROR: while copy '${img}' to '/run/archiso/copytoram/${img_fullname}'"
             launch_interactive_shell
         fi
         img="/run/archiso/copytoram/${img_fullname}"
         msg "done."
     fi
-    sfs_dev=$(losetup --find --show --read-only "${img}")
-    echo ${sfs_dev} >> /run/archiso/used_block_devices
+    sfs_dev="$(losetup --find --show --read-only -- "${img}")"
+    echo "${sfs_dev}" >> /run/archiso/used_block_devices
     _mnt_dev "${sfs_dev}" "${mnt}" "-r" "defaults"
 }
 
@@ -102,45 +108,46 @@ _mnt_dev() {
 
 _verify_checksum() {
     local _status
-    cd "/run/archiso/bootmnt/${archisobasedir}/${arch}"
+    cd "/run/archiso/bootmnt/${archisobasedir}/${arch}" || exit 1
     sha512sum -c airootfs.sha512 > /tmp/checksum.log 2>&1
     _status=$?
-    cd "${OLDPWD}"
-    return ${_status}
+    cd -- "${OLDPWD}" || exit 1
+    return "${_status}"
 }
 
 _verify_signature() {
     local _status
-    cd "/run/archiso/bootmnt/${archisobasedir}/${arch}"
+    cd "/run/archiso/bootmnt/${archisobasedir}/${arch}" || exit 1
     gpg --homedir /gpg --status-fd 1 --verify airootfs.sfs.sig 2>/dev/null | grep -qE '^\[GNUPG:\] GOODSIG'
     _status=$?
-    cd "${OLDPWD}"
+    cd -- "${OLDPWD}" || exit 1
     return ${_status}
 }
 
 run_hook() {
-    [[ -z "${arch}" ]] && arch="$(uname -m)"
-    [[ -z "${copytoram_size}" ]] && copytoram_size="75%"
-    [[ -z "${archisobasedir}" ]] && archisobasedir="arch"
-    [[ -z "${dm_snap_prefix}" ]] && dm_snap_prefix="arch"
-    [[ -z "${archisodevice}" ]] && archisodevice="/dev/disk/by-label/${archisolabel}"
-    [[ -z "${cow_spacesize}" ]] && cow_spacesize="256M"
-
-    if [[ -n "${cow_label}" ]]; then
+    [ -z "${arch}" ] && arch="$(uname -m)"
+    [ -z "${copytoram_size}" ] && copytoram_size="75%"
+    [ -z "${archisobasedir}" ] && archisobasedir="arch"
+    [ -z "${dm_snap_prefix}" ] && dm_snap_prefix="arch"
+    # shellcheck disable=SC2154 # defined via initcpio's parse_cmdline()
+    [ -z "${archisodevice}" ] && archisodevice="/dev/disk/by-label/${archisolabel}"
+    [ -z "${cow_spacesize}" ] && cow_spacesize="256M"
+    # shellcheck disable=SC2154 # defined via initcpio's parse_cmdline()
+    if [ -n "${cow_label}" ]; then
         cow_device="/dev/disk/by-label/${cow_label}"
-        [[ -z "${cow_persistent}" ]] && cow_persistent="P"
-    elif [[ -n "${cow_device}" ]]; then
-        [[ -z "${cow_persistent}" ]] && cow_persistent="P"
+        [ -z "${cow_persistent}" ] && cow_persistent="P"
+    elif [ -n "${cow_device}" ]; then
+        [ -z "${cow_persistent}" ] && cow_persistent="P"
     else
         cow_persistent="N"
     fi
 
-    [[ -z "${cow_flags}" ]] && cow_flags="defaults"
-    [[ -z "${cow_directory}" ]] && cow_directory="persistent_${archisolabel}/${arch}"
-    [[ -z "${cow_chunksize}" ]] && cow_chunksize="8"
+    [ -z "${cow_flags}" ] && cow_flags="defaults"
+    [ -z "${cow_directory}" ] && cow_directory="persistent_${archisolabel}/${arch}"
+    [ -z "${cow_chunksize}" ] && cow_chunksize="8"
 
     # set mount handler for archiso
-    mount_handler="archiso_mount_handler"
+    export mount_handler="archiso_mount_handler"
 }
 
 # This function is called normally from init script, but it can be called
@@ -151,13 +158,14 @@ archiso_mount_handler() {
 
     if ! mountpoint -q "/run/archiso/bootmnt"; then
         _mnt_dev "${archisodevice}" "/run/archiso/bootmnt" "-r" "defaults"
-        if [[ "${copytoram}" != "y" ]]; then
-            echo $(readlink -f ${archisodevice}) >> /run/archiso/used_block_devices
+        if [ "${copytoram}" != "y" ]; then
+            readlink -f "${archisodevice}" >> /run/archiso/used_block_devices
         fi
     fi
 
-    if [[ "${checksum}" == "y" ]]; then
-        if [[ -f "/run/archiso/bootmnt/${archisobasedir}/${arch}/airootfs.sha512" ]]; then
+    # shellcheck disable=SC2154 # defined via initcpio's parse_cmdline()
+    if [ "${checksum}" = "y" ]; then
+        if [ -f "/run/archiso/bootmnt/${archisobasedir}/${arch}/airootfs.sha512" ]; then
             msg -n ":: Self-test requested, please wait..."
             if _verify_checksum; then
                 msg "done. Checksum is OK, continue booting."
@@ -172,8 +180,9 @@ archiso_mount_handler() {
         fi
     fi
 
-    if [[ "${verify}" == "y" ]]; then
-        if [[ -f "/run/archiso/bootmnt/${archisobasedir}/${arch}/airootfs.sfs.sig" ]]; then
+    # shellcheck disable=SC2154 # defined via initcpio's parse_cmdline()
+    if [ "${verify}" = "y" ]; then
+        if [ -f "/run/archiso/bootmnt/${archisobasedir}/${arch}/airootfs.sfs.sig" ]; then
             msg -n ":: Signature verification requested, please wait..."
             if _verify_signature; then
                 msg "done. Signature is OK, continue booting."
@@ -187,33 +196,34 @@ archiso_mount_handler() {
         fi
     fi
 
-    if [[ "${copytoram}" == "y" ]]; then
+    if [ "${copytoram}" = "y" ]; then
         msg ":: Mounting /run/archiso/copytoram (tmpfs) filesystem, size=${copytoram_size}"
         mkdir -p /run/archiso/copytoram
         mount -t tmpfs -o "size=${copytoram_size}",mode=0755 copytoram /run/archiso/copytoram
     fi
 
-    if [[ -n "${cow_device}" ]]; then
+    if [ -n "${cow_device}" ]; then
         _mnt_dev "${cow_device}" "/run/archiso/cowspace" "-r" "${cow_flags}"
-        echo $(readlink -f ${cow_device}) >> /run/archiso/used_block_devices
+        readlink -f "${cow_device}" >> /run/archiso/used_block_devices
         mount -o remount,rw "/run/archiso/cowspace"
     else
         msg ":: Mounting /run/archiso/cowspace (tmpfs) filesystem, size=${cow_spacesize}..."
         mkdir -p /run/archiso/cowspace
         mount -t tmpfs -o "size=${cow_spacesize}",mode=0755 cowspace /run/archiso/cowspace
     fi
-    mkdir -p -m 0700 "/run/archiso/cowspace/${cow_directory}"
+    mkdir -p "/run/archiso/cowspace/${cow_directory}"
+    chmod 0700 "/run/archiso/cowspace/${cow_directory}"
 
     _mnt_sfs "/run/archiso/bootmnt/${archisobasedir}/${arch}/airootfs.sfs" "/run/archiso/sfs/airootfs"
-    if [[ -f "/run/archiso/sfs/airootfs/airootfs.img" ]]; then
+    if [ -f "/run/archiso/sfs/airootfs/airootfs.img" ]; then
         _mnt_dmsnapshot "/run/archiso/sfs/airootfs/airootfs.img" "${newroot}" "/"
     else
         _mnt_overlayfs "/run/archiso/sfs/airootfs" "${newroot}" "/"
     fi
 
-    if [[ "${copytoram}" == "y" ]]; then
+    if [ "${copytoram}" = "y" ]; then
         umount -d /run/archiso/bootmnt
     fi
 }
 
-# vim:ft=sh:ts=4:sw=4:et:
+# vim: set ft=sh:
diff --git a/archiso/initcpio/hooks/archiso_loop_mnt b/archiso/initcpio/hooks/archiso_loop_mnt
index 2e99404..c32a544 100644
--- a/archiso/initcpio/hooks/archiso_loop_mnt
+++ b/archiso/initcpio/hooks/archiso_loop_mnt
@@ -1,10 +1,12 @@
-# vim: set ft=sh:
+#!/bin/ash
 
 run_hook () {
-    [[ -n "${img_label}" ]] && img_dev="/dev/disk/by-label/${img_label}"
-    [[ -z "${img_flags}" ]] && img_flags="defaults"
-    if [[ -n "${img_dev}" && -n "${img_loop}" ]]; then
-        mount_handler="archiso_loop_mount_handler"
+    # shellcheck disable=SC2154 # defined via initcpio's parse_cmdline()
+    [ -n "${img_label}" ] && img_dev="/dev/disk/by-label/${img_label}"
+    [ -z "${img_flags}" ] && img_flags="defaults"
+    # shellcheck disable=SC2154 # defined via initcpio's parse_cmdline()
+    if [ -n "${img_dev}" ] && [ -n "${img_loop}" ]; then
+        export mount_handler="archiso_loop_mount_handler"
     fi
 }
 
@@ -15,21 +17,24 @@ archiso_loop_mount_handler () {
 
     msg ":: Setup a loop device from ${img_loop} located at device ${img_dev}"
     _mnt_dev "${img_dev}" "/run/archiso/img_dev" "-r" "${img_flags}"
-    if [[ "${copytoram}" != "y" ]]; then
-        echo $(readlink -f ${img_dev}) >> /run/archiso/used_block_devices
+    # shellcheck disable=SC2154 # defined via initcpio's parse_cmdline()
+    if [ "${copytoram}" != "y" ]; then
+        readlink -f "${img_dev}" >> /run/archiso/used_block_devices
     fi
 
     if _dev_loop=$(losetup --find --show --read-only "/run/archiso/img_dev/${img_loop}"); then
-        archisodevice="${_dev_loop}"
+        export archisodevice="${_dev_loop}"
     else
         echo "ERROR: Setting loopback device for file '/run/archiso/img_dev/${img_loop}'"
         launch_interactive_shell
     fi
 
-    archiso_mount_handler ${newroot}
+    archiso_mount_handler "${newroot}"
 
-    if [[ "${copytoram}" == "y" ]]; then
-        losetup -d ${_dev_loop} 2>/dev/null
+    if [ "${copytoram}" = "y" ]; then
+        losetup -d "${_dev_loop}" 2>/dev/null
         umount /run/archiso/img_dev
     fi
 }
+
+# vim: set ft=sh:
diff --git a/archiso/initcpio/hooks/archiso_pxe_common b/archiso/initcpio/hooks/archiso_pxe_common
index 2380ca3..e31903e 100644
--- a/archiso/initcpio/hooks/archiso_pxe_common
+++ b/archiso/initcpio/hooks/archiso_pxe_common
@@ -1,55 +1,55 @@
-# vim: set ft=sh:
+#!/bin/ash
 
 run_hook () {
     # Do *not* declare 'bootif_dev' local! We need it in run_latehook().
     local i net_mac bootif_mac
+    local DNSDOMAIN HOSTNAME IPV4DNS0 IPV4DNS1 ROOTSERVER
     # These variables will be parsed from /tmp/net-*.conf generated by ipconfig
-    local DEVICE
-    local IPV4ADDR IPV4BROADCAST IPV4NETMASK IPV4GATEWAY IPV4DNS0 IPV4DNS1
-    local HOSTNAME DNSDOMAIN NISDOMAIN ROOTSERVER ROOTPATH
-    local filename
-    # /tmp/net-*.conf
+    # shellcheck disable=SC2034
+    local DEVICE IPV4ADDR IPV4BROADCAST IPV4NETMASK IPV4GATEWAY NISDOMAIN ROOTPATH filename
 
-    if [[ -n "${ip}" ]]; then
-        if [[ -n "${BOOTIF}" ]]; then
-            bootif_mac=${BOOTIF#01-}
-            bootif_mac=${bootif_mac//-/:}
+    if [ -n "${ip}" ]; then
+        if [ -n "${BOOTIF}" ]; then
+            bootif_mac="${BOOTIF#01-}"
+            # shellcheck disable=SC2169 # ash supports bash-like string replacment
+            bootif_mac="${bootif_mac//-/:}"
             for i in /sys/class/net/*/address; do
-                read net_mac < ${i}
-                if [[ "${bootif_mac}" == "${net_mac}" ]]; then
+                read -r net_mac < "${i}"
+                if [ "${bootif_mac}" = "${net_mac}" ]; then
                     bootif_dev=${i#/sys/class/net/}
                     bootif_dev=${bootif_dev%/address}
                     break
                 fi
             done
-	    if [[ "${ip}" == "dhcp" ]]; then
+            if [ "${ip}" = "dhcp" ]; then
                 ip=":::::${bootif_dev}:dhcp"
-	    else
+            else
                 ip="${ip}::${bootif_dev}"
             fi
         fi
 
         # setup network and save some values
         if ! ipconfig -t 20 "ip=${ip}"; then
-                echo "ERROR; Failed to configure network"
-                echo "   Falling back to interactive prompt"
-                echo "   You can try to fix the problem manually, log out when you are finished"
-                launch_interactive_shell
+            echo "ERROR; Failed to configure network"
+            echo "   Falling back to interactive prompt"
+            echo "   You can try to fix the problem manually, log out when you are finished"
+            launch_interactive_shell
         fi
 
+        # shellcheck disable=SC1090 # ipconfig generates these files
         . /tmp/net-*.conf
 
-        pxeserver=${ROOTSERVER}
+        export pxeserver="${ROOTSERVER}"
 
         # setup DNS resolver
-        if [[ "${IPV4DNS0}" != "0.0.0.0" ]]; then
+        if [ "${IPV4DNS0}" != "0.0.0.0" ]; then
             echo "# added by archiso_pxe_common hook" > /etc/resolv.conf
             echo "nameserver ${IPV4DNS0}" >> /etc/resolv.conf
         fi
-        if [[ "${IPV4DNS1}" != "0.0.0.0" ]]; then
+        if [ "${IPV4DNS1}" != "0.0.0.0" ]; then
             echo "nameserver ${IPV4DNS1}" >> /etc/resolv.conf
         fi
-        if [[ -n "${DNSDOMAIN}" ]]; then
+        if [ -n "${DNSDOMAIN}" ]; then
             echo "search ${DNSDOMAIN}" >> /etc/resolv.conf
             echo "domain ${DNSDOMAIN}" >> /etc/resolv.conf
         fi
@@ -57,16 +57,19 @@ run_hook () {
 }
 
 run_latehook () {
-    if [[ -n "${ip}" ]]; then
-        [[ -z "${copy_resolvconf}" ]] && copy_resolvconf="y"
+    if [ -n "${ip}" ]; then
+        [ -z "${copy_resolvconf}" ] && copy_resolvconf="y"
 
-        if [[ "${copytoram}" == "y" ]]; then
-            if [[ -n "${bootif_dev}" ]]; then
+        # shellcheck disable=SC2154 # defined via initcpio's parse_cmdline()
+        if [ "${copytoram}" = "y" ]; then
+            if [ -n "${bootif_dev}" ]; then
                 ip addr flush dev "${bootif_dev}"
                 ip link set "${bootif_dev}" down
             fi
-        elif [[ "${copy_resolvconf}" != "n" && -f /etc/resolv.conf ]]; then
+        elif [ "${copy_resolvconf}" != "n" ] && [ -f /etc/resolv.conf ]; then
             cp /etc/resolv.conf /new_root/etc/resolv.conf
         fi
     fi
 }
+
+# vim: set ft=sh:
diff --git a/archiso/initcpio/hooks/archiso_pxe_http b/archiso/initcpio/hooks/archiso_pxe_http
index a7c03a8..5e55356 100644
--- a/archiso/initcpio/hooks/archiso_pxe_http
+++ b/archiso/initcpio/hooks/archiso_pxe_http
@@ -1,16 +1,17 @@
-# vim: set ft=sh:
+#!/bin/ash
 
 run_hook() {
-    if [[ -n "${ip}" && -n "${archiso_http_srv}" ]]; then
+    # shellcheck disable=SC2154 # defined via initcpio's parse_cmdline()
+    if [ -n "${ip}" ] && [ -n "${archiso_http_srv}" ]; then
 
         # booting with http is always copy-to-ram, so set here to make sure
         # addresses are flushed and interface is set down
-        copytoram="y"
+        export copytoram="y"
 
-        archiso_http_srv=$(eval echo ${archiso_http_srv})
-        [[ -z "${archiso_http_spc}" ]] && archiso_http_spc="75%"
+        archiso_http_srv=$(eval echo "${archiso_http_srv}")
+        [ -z "${archiso_http_spc}" ] && archiso_http_spc="75%"
 
-        mount_handler="archiso_pxe_http_mount_handler"
+        export mount_handler="archiso_pxe_http_mount_handler"
     fi
 }
 
@@ -23,6 +24,7 @@ _curl_get() {
     local _dst="${2}"
 
     msg ":: Downloading '${_url}'"
+    # shellcheck disable=SC2154 # defined via initcpio's parse_cmdline()
     if ! curl -L -f -o "/run/archiso/httpspace/${archisobasedir}${_dst}/${_url##*/}" --create-dirs "${_url}"; then
         echo "ERROR: Downloading '${_url}'"
         echo "   Falling back to interactive prompt"
@@ -38,17 +40,22 @@ archiso_pxe_http_mount_handler () {
     mkdir -p "/run/archiso/httpspace"
     mount -t tmpfs -o size="${archiso_http_spc}",mode=0755 httpspace "/run/archiso/httpspace"
 
+    # shellcheck disable=SC2154 # defined via initcpio's parse_cmdline()
     _curl_get "${archiso_http_srv}${archisobasedir}/${arch}/airootfs.sfs" "/${arch}"
 
-    if [[ "${checksum}" == "y" ]]; then
+    # shellcheck disable=SC2154 # defined via initcpio's parse_cmdline()
+    if [ "${checksum}" = "y" ]; then
         _curl_get "${archiso_http_srv}${archisobasedir}/${arch}/airootfs.sha512" "/${arch}"
     fi
-    if [[ "${verify}" == "y" ]]; then
+    # shellcheck disable=SC2154 # defined via initcpio's parse_cmdline()
+    if [ "${verify}" = "y" ]; then
         _curl_get "${archiso_http_srv}${archisobasedir}/${arch}/airootfs.sfs.sig" "/${arch}"
     fi
 
     mkdir -p "/run/archiso/bootmnt"
     mount -o bind /run/archiso/httpspace /run/archiso/bootmnt
 
-    archiso_mount_handler ${newroot}
+    archiso_mount_handler "${newroot}"
 }
+
+# vim: set ft=sh:
diff --git a/archiso/initcpio/hooks/archiso_pxe_nbd b/archiso/initcpio/hooks/archiso_pxe_nbd
index 4fb7fa5..ce93080 100644
--- a/archiso/initcpio/hooks/archiso_pxe_nbd
+++ b/archiso/initcpio/hooks/archiso_pxe_nbd
@@ -1,19 +1,20 @@
-# vim: set ft=sh:
+#!/bin/ash
 
 run_earlyhook() {
-    if [[ -n "${ip}" && -n "${archiso_nbd_srv}" ]]; then
+    # shellcheck disable=SC2154 # defined via initcpio's parse_cmdline()
+    if [ -n "${ip}" ] && [ -n "${archiso_nbd_srv}" ]; then
         # Module autoloading like with loop devices does not work, doing manually...
         modprobe nbd 2> /dev/null
     fi
 }
 
 run_hook() {
-    if [[ -n "${ip}" && -n "${archiso_nbd_srv}" ]]; then
+    if [ -n "${ip}" ] && [ -n "${archiso_nbd_srv}" ]; then
 
-        archiso_nbd_srv=$(eval echo ${archiso_nbd_srv})
-        [[ -z "${archiso_nbd_name}" ]] && archiso_nbd_name="archiso"
+        archiso_nbd_srv=$(eval echo "${archiso_nbd_srv}")
+        [ -z "${archiso_nbd_name}" ] && archiso_nbd_name="archiso"
 
-        mount_handler="archiso_pxe_nbd_mount_handler"
+        export mount_handler="archiso_pxe_nbd_mount_handler"
     fi
 }
 
@@ -29,19 +30,21 @@ archiso_pxe_nbd_mount_handler () {
     done
 
     msg ":: Setup NBD from ${archiso_nbd_srv} at /dev/nbd0"
-    if [[ "${copytoram}" != "n" ]]; then
-        nbd-client ${archiso_nbd_srv} -N ${archiso_nbd_name} /dev/nbd0
+    if [ "${copytoram}" != "n" ]; then
+        nbd-client "${archiso_nbd_srv}" -N "${archiso_nbd_name}" /dev/nbd0
         copytoram="y"
     else
-        nbd-client ${archiso_nbd_srv} -N ${archiso_nbd_name} -systemd-mark -persist /dev/nbd0
+        nbd-client "${archiso_nbd_srv}" -N "${archiso_nbd_name}" -systemd-mark -persist /dev/nbd0
     fi
 
-    archisodevice=/dev/nbd0
+    export archisodevice=/dev/nbd0
 
-    archiso_mount_handler ${newroot}
+    archiso_mount_handler "${newroot}"
 
-    if [[ "${copytoram}" == "y" ]]; then
+    if [ "${copytoram}" = "y" ]; then
         msg ":: Disconnect NBD from ${archiso_nbd_srv} at /dev/nbd0"
         nbd-client -d /dev/nbd0
     fi
 }
+
+# vim: set ft=sh:
diff --git a/archiso/initcpio/hooks/archiso_pxe_nfs b/archiso/initcpio/hooks/archiso_pxe_nfs
index 67874ec..406541b 100644
--- a/archiso/initcpio/hooks/archiso_pxe_nfs
+++ b/archiso/initcpio/hooks/archiso_pxe_nfs
@@ -1,30 +1,40 @@
-# vim: set ft=sh:
+#!/bin/ash
 
 run_hook() {
-    if [[ -n "${ip}" && -n "${archiso_nfs_srv}" ]]; then
+    # shellcheck disable=SC2154 # defined via initcpio's parse_cmdline()
+    if [ -n "${ip}" ] && [ -n "${archiso_nfs_srv}" ]; then
 
-        archiso_nfs_srv=$(eval echo ${archiso_nfs_srv})
-        [[ -n "${archiso_nfs_opt}" ]] && archiso_nfs_opt="-o ${archiso_nfs_opt}"
+        archiso_nfs_srv=$(eval echo "${archiso_nfs_srv}")
 
-        mount_handler="archiso_nfs_mount_handler"
+        export mount_handler="archiso_nfs_mount_handler"
     fi
 }
 
 archiso_nfs_mount_handler() {
+    local mount_status
     newroot="${1}"
     mkdir -p "/run/archiso/bootmnt"
     msg ":: Mounting '${archiso_nfs_srv}'"
-    # Do not put "${archiso_nfs_opt}" nfsmount fails!
-    if ! nfsmount ${archiso_nfs_opt} "${archiso_nfs_srv}" "/run/archiso/bootmnt"; then
+    # shellcheck disable=SC2154 # defined via initcpio's parse_cmdline()
+    if [ -n "${archiso_nfs_opt}" ]; then
+        nfsmount -o "${archiso_nfs_opt}" "${archiso_nfs_srv}" "/run/archiso/bootmnt"
+        mount_status=$?
+    else
+        nfsmount "${archiso_nfs_srv}" "/run/archiso/bootmnt"
+        mount_status=$?
+    fi
+    if [ $mount_status -gt 0 ]; then
         echo "ERROR: Mounting '${archiso_nfs_srv}'"
         echo "   Falling back to interactive prompt"
         echo "   You can try to fix the problem manually, log out when you are finished"
         launch_interactive_shell
     fi
 
-    if [[ "${copytoram}" != "n" ]]; then
+    if [ "${copytoram}" != "n" ]; then
         copytoram="y"
     fi
 
-    archiso_mount_handler ${newroot}
+    archiso_mount_handler "${newroot}"
 }
+
+# vim: set ft=sh:
diff --git a/archiso/initcpio/hooks/archiso_shutdown b/archiso/initcpio/hooks/archiso_shutdown
index e50dedb..db8fb33 100644
--- a/archiso/initcpio/hooks/archiso_shutdown
+++ b/archiso/initcpio/hooks/archiso_shutdown
@@ -1,6 +1,8 @@
+#!/bin/ash
+
 run_cleanuphook() {
     rm -rf /usr/lib/modules
     cp -ax / /run/initramfs
 }
 
-# vim: set ft=sh ts=4 sw=4 et:
+# vim: set ft=sh:
diff --git a/archiso/initcpio/install/archiso b/archiso/initcpio/install/archiso
index 30728ef..a12104e 100644
--- a/archiso/initcpio/install/archiso
+++ b/archiso/initcpio/install/archiso
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 build() {
     add_module "cdrom"
@@ -22,9 +22,7 @@ build() {
     add_file /usr/lib/udev/rules.d/95-dm-notify.rules
     add_file /usr/lib/initcpio/udev/11-dm-initramfs.rules /usr/lib/udev/rules.d/11-dm-initramfs.rules
     if [[ $ARCHISO_GNUPG_FD ]]; then
-        mkdir -p "$BUILDROOT$dest"/gpg
-        gpg --homedir "$BUILDROOT$dest"/gpg --import <&$ARCHISO_GNUPG_FD
+        mkdir -p "$BUILDROOT/gpg"
+        gpg --homedir "$BUILDROOT/gpg" --import <& "$ARCHISO_GNUPG_FD"
     fi
 }
-
-# vim: set ft=sh ts=4 sw=4 et:
diff --git a/archiso/initcpio/install/archiso_kms b/archiso/initcpio/install/archiso_kms
index bfb2d48..48832ff 100644
--- a/archiso/initcpio/install/archiso_kms
+++ b/archiso/initcpio/install/archiso_kms
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 build() {
     add_module "amdgpu"
diff --git a/archiso/initcpio/install/archiso_loop_mnt b/archiso/initcpio/install/archiso_loop_mnt
index 59f1d94..4a5824d 100644
--- a/archiso/initcpio/install/archiso_loop_mnt
+++ b/archiso/initcpio/install/archiso_loop_mnt
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 build() {
     add_runscript
@@ -9,5 +9,3 @@ cat<<HELPEOF
   This hook loads the necessary modules for boot via loop device.
 HELPEOF
 }
-
-# vim: set ft=sh ts=4 sw=4 et:
diff --git a/archiso/initcpio/install/archiso_pxe_common b/archiso/initcpio/install/archiso_pxe_common
index eec9a7e..da5f6b6 100644
--- a/archiso/initcpio/install/archiso_pxe_common
+++ b/archiso/initcpio/install/archiso_pxe_common
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 build() {
     add_checked_modules -f "(irda|phy|wimax|wireless|ppp_|plip|pppoe)" "/drivers/net/"
@@ -8,13 +8,13 @@ build() {
     add_binary /usr/lib/initcpio/ipconfig /bin/ipconfig
 
     # Add hosts support files+dns
-    add_symlink /usr/lib/libnss_files.so.2 $(readlink /usr/lib/libnss_files.so.2)
-    add_binary $(readlink -f /usr/lib/libnss_files.so.2)
-    add_symlink /usr/lib/libnss_dns.so.2 $(readlink /usr/lib/libnss_dns.so.2)
-    add_binary $(readlink -f /usr/lib/libnss_dns.so.2)
+    add_symlink /usr/lib/libnss_files.so.2 "$(readlink /usr/lib/libnss_files.so.2)"
+    add_binary "$(readlink -f /usr/lib/libnss_files.so.2)"
+    add_symlink /usr/lib/libnss_dns.so.2 "$(readlink /usr/lib/libnss_dns.so.2)"
+    add_binary "$(readlink -f /usr/lib/libnss_dns.so.2)"
 
     add_dir /etc
-    echo "hosts: files dns" > $BUILDROOT/etc/nsswitch.conf
+    echo "hosts: files dns" > "$BUILDROOT/etc/nsswitch.conf"
 }
 
 help() {
@@ -22,5 +22,3 @@ cat<<HELPEOF
   This hook loads the necessary modules for boot via PXE.
 HELPEOF
 }
-
-# vim: set ft=sh ts=4 sw=4 et:
diff --git a/archiso/initcpio/install/archiso_pxe_http b/archiso/initcpio/install/archiso_pxe_http
index 9ce9726..3353eb7 100644
--- a/archiso/initcpio/install/archiso_pxe_http
+++ b/archiso/initcpio/install/archiso_pxe_http
@@ -1,11 +1,11 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 build() {
     add_runscript
 
     add_binary curl
 
-    add_file $(readlink -f /etc/ssl/certs/ca-certificates.crt) /etc/ssl/certs/ca-certificates.crt
+    add_file "$(readlink -f /etc/ssl/certs/ca-certificates.crt)" /etc/ssl/certs/ca-certificates.crt
 }
 
 help() {
@@ -13,5 +13,3 @@ cat<<HELPEOF
   This hook loads the necessary modules for boot via PXE and HTTP.
 HELPEOF
 }
-
-# vim: set ft=sh ts=4 sw=4 et:
diff --git a/archiso/initcpio/install/archiso_pxe_nbd b/archiso/initcpio/install/archiso_pxe_nbd
index 47d98ce..9fe3fdd 100644
--- a/archiso/initcpio/install/archiso_pxe_nbd
+++ b/archiso/initcpio/install/archiso_pxe_nbd
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 build() {
     add_module "nbd"
@@ -13,5 +13,3 @@ cat<<HELPEOF
   This hook loads the necessary modules for boot via PXE and NBD.
 HELPEOF
 }
-
-# vim: set ft=sh ts=4 sw=4 et:
diff --git a/archiso/initcpio/install/archiso_pxe_nfs b/archiso/initcpio/install/archiso_pxe_nfs
index f8226e5..fa4e548 100644
--- a/archiso/initcpio/install/archiso_pxe_nfs
+++ b/archiso/initcpio/install/archiso_pxe_nfs
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 build() {
     add_module "nfs"
@@ -13,5 +13,3 @@ help() {
   This hook loads the necessary modules for boot via PXE and NFS.
 HELPEOF
 }
-
-# vim: set ft=sh ts=4 sw=4 et:
diff --git a/archiso/initcpio/install/archiso_shutdown b/archiso/initcpio/install/archiso_shutdown
index 5ae976a..1051d1b 100644
--- a/archiso/initcpio/install/archiso_shutdown
+++ b/archiso/initcpio/install/archiso_shutdown
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 build() {
     add_binary cp
@@ -12,9 +12,7 @@ help() {
     cat <<HELPEOF
 This hook will create a shutdown initramfs in /run/initramfs
 that we can pivot to on shutdown in order to unmount / and
-and others mount points, dm-snapshot devices and loopback devices.
-Mostly usefull for dm-snapshot persistent.
+and other mount points, dm-snapshot and loopback devices.
+Mostly useful for persistent dm-snapshot.
 HELPEOF
 }
-
-# vim: set ft=sh ts=4 sw=4 et:
diff --git a/archiso/initcpio/script/archiso_shutdown b/archiso/initcpio/script/archiso_shutdown
index 41b3945..4a0c7dc 100644
--- a/archiso/initcpio/script/archiso_shutdown
+++ b/archiso/initcpio/script/archiso_shutdown
@@ -5,15 +5,15 @@ mkdir /oldrun
 mount -n --move /oldroot/run /oldrun
 
 # Unmount all mounts now.
-umount $(mount | awk '$3 ~/^\/oldroot/ {print $3}' | sort -r)
+umount "$(mount | awk '$3 ~/^\/oldroot/ {print $3}' | sort -r)"
 
 # Remove all dm-snapshot devices.
 dmsetup remove_all
 
 # Remove all loopback devices.
 for _lup in $(grep ^/dev/loop /oldrun/archiso/used_block_devices | tac); do
-    if ! losetup -d ${_lup} 2> /dev/null; then
-        umount -d ${_lup}
+    if ! losetup -d -- "${_lup}" 2> /dev/null; then
+        umount -d -- "${_lup}"
     fi
 done
 
@@ -21,8 +21,8 @@ done
 umount /oldrun/archiso/cowspace
 
 # Unmount boot device if needed (no copytoram=y used)
-if [[ ! -d /oldrun/archiso/copytoram ]]; then
-    if [[ -d /oldrun/archiso/img_dev ]]; then
+if [ ! -d /oldrun/archiso/copytoram ]; then
+    if [ -d /oldrun/archiso/img_dev ]; then
         umount /oldrun/archiso/img_dev
     else
         umount /oldrun/archiso/bootmnt
@@ -35,3 +35,5 @@ case "$1" in
   reboot|poweroff|halt) "$1" -f ;;
   *) halt -f;;
 esac
+
+# vim: set ft=sh: