grml2iso: make sure to exit properly if provided argument to -c option does not exist

Otherwise we're hiding the actual error message.

diff --git a/grml2iso b/grml2iso
index 0addfb7..8f4d7b8 100755 (executable)
--- a/grml2iso
+++ b/grml2iso
@@ -86,7 +86,7 @@ Options:
     case $name in
       o)   ISOFILE="$OPTARG";;
       b)   GRML2USB_OPTS+=(--bootoptions="$OPTARG");;
     case $name in
       o)   ISOFILE="$OPTARG";;
       b)   GRML2USB_OPTS+=(--bootoptions="$OPTARG");;

-      c)   DIR="$(readlink -f "$OPTARG")";;
+      c)   DIR="$(readlink -f "$OPTARG")"; [ -n "$DIR" ] || { echo "Could not read $OPTARG - exiting" >&2 ; exit 1 ; } ;;

       f)   FORCE='true';;
       r)   GRML2USB_OPTS+=(--remove-bootoption="$OPTARG");;
       p)   GRML2USB_OPTS+=("$OPTARG");;
       f)   FORCE='true';;
       r)   GRML2USB_OPTS+=(--remove-bootoption="$OPTARG");;
       p)   GRML2USB_OPTS+=("$OPTARG");;