Meta: Fix shellcheck warnings in various scripts

Warnings fixed:
 * SC2086: Double quote to prevent globbing and word splitting.
 * SC2006: Use $(...) notation instead of legacy backticked `...`
 * SC2039: In POSIX sh, echo flags are undefined
 * SC2209: Use var=$(command) to assign output (or quote to assign string)
 * SC2164: Use 'cd ... || exit' or 'cd ... || return' in case cd fails
 * SC2166: Prefer [ p ] && [ q ] as [ p -a q ] is not well defined.
 * SC2034: i appears unused. Verify use (or export if used externally)
 * SC2046: Quote this to prevent word splitting.
 * SC2236: Use -z instead of ! -n.

There are still a lot of warnings in Kernel/run about:
 - SC2086: Double quote to prevent globbing and word splitting.

However, splitting on space is intentional in this case, and not trivial to
change. Therefore ignore the warning for now - but we should fix this in
the future.

Kernel/build-image-qemu.sh

@@ -15,32 +15,32 @@ if [ "$(uname -s)" = "Darwin" ]; then
  export PATH="/usr/local/opt/e2fsprogs/sbin:$PATH"
 fi
 echo "setting up disk image..."
-qemu-img create _disk_image "${DISK_SIZE:-600}"m || die "couldn't create disk image"
-chown "$SUDO_UID":"$SUDO_GID" _disk_image || die "couldn't adjust permissions on disk image"
+qemu-img create _disk_image "${DISK_SIZE:-600}"m || die "could not create disk image"
+chown "$SUDO_UID":"$SUDO_GID" _disk_image || die "could not adjust permissions on disk image"
 echo "done"
 
 printf "creating new filesystem... "
 if [ "$(uname -s)" = "OpenBSD" ]; then
- VND=`vnconfig _disk_image`
- (echo "e 0"; echo 83; echo n; echo 0; echo "*"; echo "quit") | fdisk -e $VND
- mkfs.ext2 -I 128 -F /dev/${VND}i || die "couldn't create filesystem"
+ VND=$(vnconfig _disk_image)
+ (echo "e 0"; echo 83; echo n; echo 0; echo "*"; echo "quit") | fdisk -e "$VND"
+ mkfs.ext2 -I 128 -F "/dev/${VND}i" || die "could not create filesystem"
 else
  if [ -x /sbin/mke2fs ]; then
- /sbin/mke2fs -q -I 128 _disk_image || die "couldn't create filesystem"
+ /sbin/mke2fs -q -I 128 _disk_image || die "could not create filesystem"
  else
- mke2fs -q -I 128 _disk_image || die "couldn't create filesystem"
+ mke2fs -q -I 128 _disk_image || die "could not create filesystem"
  fi
 fi
 echo "done"
 
 printf "mounting filesystem... "
 mkdir -p mnt
 if [ "$(uname -s)" = "Darwin" ]; then
- fuse-ext2 _disk_image mnt -o rw+,allow_other,uid=501,gid=20 || die "couldn't mount filesystem"
+ fuse-ext2 _disk_image mnt -o rw+,allow_other,uid=501,gid=20 || die "could not mount filesystem"
 elif [ "$(uname -s)" = "OpenBSD" ]; then
- mount -t ext2fs /dev/${VND}i mnt/ || die "couldn't mount filesystem"
+ mount -t ext2fs "/dev/${VND}i" mnt/ || die "could not mount filesystem"
 else
- mount _disk_image mnt/ || die "couldn't mount filesystem"
+ mount _disk_image mnt/ || die "could not mount filesystem"
 fi
 echo "done"
 
@@ -50,7 +50,7 @@ cleanup() {
  umount mnt || ( sleep 1 && sync && umount mnt )
  rm -rf mnt
  if [ "$(uname -s)" = "OpenBSD" ]; then
- vnconfig -u $VND
+ vnconfig -u "$VND"
  fi
  echo "done"
  fi

Kernel/makeall.sh

@@ -9,7 +9,7 @@ while [ "$1" != "" ]; do
  case $1 in
  -f | --fast ) fast_mode=1
  ;;
- -h | --help ) echo "-f or --fast: build fast without cleaning or running tests"
+ -h | --help ) printf -- "-f or --fast: build fast without cleaning or running tests\n"
  exit 0
  ;;
  esac
@@ -18,10 +18,10 @@ done
 
 sudo id
 
-MAKE=make
+MAKE="make"
 
 if [ "$(uname -s)" = "OpenBSD" ]; then
- MAKE=gmake
+ MAKE="gmake"
 fi
 
 if [ "$fast_mode" = "1" ]; then

Kernel/mkmap.sh

@@ -1,6 +1,6 @@
 #!/bin/sh
 tmp=$(mktemp)
-nm -n kernel | awk '{ if ($2 != "a") print; }' | uniq > $tmp
-printf "%08x\n" $(wc -l $tmp | cut -f1 -d' ') > kernel.map
-cat $tmp >> kernel.map
-rm -f $tmp
+nm -n kernel | awk '{ if ($2 != "a") print; }' | uniq > "$tmp"
+printf "%08x\n" "$(wc -l "$tmp" | cut -f1 -d' ')" > kernel.map
+cat "$tmp" >> kernel.map
+rm -f "$tmp"

Kernel/run

@@ -1,11 +1,14 @@
 #!/bin/sh
+# shellcheck disable=SC2086 # FIXME: fix these globing warnings
+
+set -e
 
 script_path=$(cd -P -- "$(dirname -- "$0")" && pwd -P)
 cd "$script_path"
 
 #SERENITY_PACKET_LOGGING_ARG="-object filter-dump,id=hue,netdev=breh,file=e1000.pcap"
 
-[ -e /dev/kvm -a -r /dev/kvm -a -w /dev/kvm ] && SERENITY_KVM_ARG="-enable-kvm"
+[ -e /dev/kvm ] && [ -r /dev/kvm ] && [ -w /dev/kvm ] && SERENITY_KVM_ARG="-enable-kvm"
 
 [ -z "$SERENITY_BOCHS_BIN" ] && SERENITY_BOCHS_BIN="bochs"
 
@@ -33,7 +36,7 @@ $SERENITY_EXTRA_QEMU_ARGS
 -s -m $SERENITY_RAM_SIZE
 -cpu max
 -machine q35
--d cpu_reset,guest_errors 
+-d cpu_reset,guest_errors
 -device VGA,vgamem_mb=64
 -device piix3-ide
 -drive file=_disk_image,id=disk,if=none
@@ -76,7 +79,7 @@ elif [ "$1" = "qgrub" ]; then
 elif [ "$1" = "q35_cmd" ]; then
  SERENITY_KERNEL_CMDLINE=""
  # FIXME: Someone who knows sh syntax better, please help:
- for i in `seq 2 $#`; do
+ for _ in $(seq 2 $#); do
  shift
  SERENITY_KERNEL_CMDLINE="$SERENITY_KERNEL_CMDLINE $1"
  done
@@ -92,7 +95,7 @@ elif [ "$1" = "q35_cmd" ]; then
 elif [ "$1" = "qcmd" ]; then
  SERENITY_KERNEL_CMDLINE=""
  # FIXME: Someone who knows sh syntax better, please help:
- for i in `seq 2 $#`; do
+ for _ in $(seq 2 $#); do
  shift