Shell Programming and Scripting

Hello, I was hoping for a second pair of eyes or a little bit of help figuring out what my error is in a script. I did some searching in the forums and didn't find anything so please forgive me if it a similar problem has been discussed before.

My script accepts normal user arguments; however, the two formats I am using are returning bad substitution errors. I could do fix it the old fashioned way with more code but I would prefer to try to figure out what is wrong with my current syntax.

Here are the snippets from the two formats I am trying to use:

Code:

while [ "$1" != "" ]
do
   if [ "${1:0:1}" = "-" ]; then
      case "$1" in
      "-v") echo "$VERSION"
           exit
          ;;
      "-h") #echo help usage
           ;;
      "-s") #do stuff
           shift
          ;;
      *)
           usage "Argument not recognized: $1"
          ;;
      esac
   fi
   shift
done

2nd example:

Code:

while [ "${1:0:1}" = "-" ]; do
   case ${1:1:1} in
   "v") echo "$VERSION"
        exit
       ;;
   "h") #echo help usage
        ;;
   "s") #do stuff
        shift
       ;;
   *)
        usage "Argument not recognized: $1"
       ;;
   esac
done

My error code:
[script name] [line_number]: Bad substitution

The line_number corresponds with the done in the loops but it's definitely with the ${1:0:1} syntax, which doesn't make sense because it's valid (at least unless my eyes are missing something).

Thanks for any help I can get!

Hi, Jackinthemox, and welcome to the forums.

That type of parameter substring expansion isn't implemented by all shells. Are you certain that the shell that's executing the script supports it?

Regards,
Alister

if you are trying to parse the command line maybe you should:

man -k getopt