chirpotle.sh: Add error message if script parameter is not set or doe…

…s not exist

chirpotle.sh

@@ -880,6 +880,7 @@ function chirpotle_run {
 
   # Parameter parsing
   while [[ $# -gt 0 ]] && [[ -z "$SCRIPTNAME" ]]; do
+    # -z is required to stop after 'scriptname' was parsed. Further arguments are passed to the script.
     KEY="$1"
     case "$KEY" in
         -c|--conf)
@@ -916,6 +917,10 @@ function chirpotle_run {
     esac
   done
   # ... all other arguments (if any) are passed to the script as positional args
+  if [[ ! -e "$SCRIPTNAME" ]]; then
+    echo "Abort: Script could not be found. (The parsed script name was: '$SCRIPTNAME')"
+    exit -1
+  fi
   while [[ $# -gt 0 ]]; do
     POSITIONAL+=("$1")
     shift