Fix shift blowup without arguments

Author: cirosantilli

rootfs_overlay/lkmc/fops.sh

@@ -4,7 +4,7 @@ set -e
 # Setup
 f=/sys/kernel/debug/lkmc_fops
 mod="${1:-fops.ko}"
-shift
+[ $# -gt 1] && shift
 insmod "$mod" "$@"
 
 # read

rootfs_overlay/lkmc/memfile.sh

@@ -9,7 +9,7 @@ odraw() (
 # Setup
 f=/sys/kernel/debug/lkmc_memfile
 mod="${1:-memfile.ko}"
-shift
+[ $# -gt 1] && shift
 insmod "$mod" "$@"
 
 # Starts off empty

rootfs_overlay/lkmc/scull.sh

@@ -4,7 +4,7 @@ set -eux
 name=scull
 
 mod="${1:-$name.ko}"
-shift
+[ $# -gt 1] && shift
 insmod "$mod" "$@"
 major="$(awk "\$2==\"$name\" {print \$1}" /proc/devices)"
 

rootfs_overlay/lkmc/seq_file.sh

@@ -2,7 +2,7 @@
 set -e
 f=/sys/kernel/debug/lkmc_seq_file
 mod="${1:-seq_file.ko}"
-shift
+[ $# -gt 1] && shift
 insmod "$mod" "$@"
 [ "$(cat "$f")" = "$(printf '0\n1\n2\n')" ]
 [ "$(cat "$f")" = "$(printf '0\n1\n2\n')" ]

rootfs_overlay/lkmc/seq_file_single_open.sh

@@ -2,7 +2,7 @@
 set -e
 f=/sys/kernel/debug/lkmc_seq_file_single_open
 mod="${1:-seq_file_single_open.ko}"
-shift
+[ $# -gt 1] && shift
 insmod "$mod" "$@"
 [ "$(cat "$f")" = "$(printf 'ab\ncd\n')" ]
 [ "$(dd if="$f" bs=1 count=3 skip=1)" = "$(printf "b\nc\n")" ]