case command and regex

[William Park]

On Sat, Mar 16, 2013 at 08:15:49PM -0400, Daniel Wayne Armstrong wrote:
> I am trying to write a usable regex for the case command in a shell
> script. For example:
> 
> ---
> 
> #!/bin/bash
> # testscript $1
> if [[ $1 =~ [\+\-]([0-9]+)+$ ]]; then
>         echo "Match is $1"
> else
>         echo "No match."
> fi
> 
> while [ $# -gt 0 ]; do
>         case $1 in
>                 [\+\-]\([0-9]+\)+$ ) echo "Match is $1"
>                                 exit
>                                 ;;
>                 * )             echo "No match."
>                                 exit
>                                 ;;
>         esac
> done
> 
> ---
> 
> ... and if I run "./testscript +77" I get:
> 
> Match is +77
> No match.
> 
> I know I have the syntax messed up somehow in the case regex example
> but I have tried it many different ways and can't seem to get it
> right. I have tried extglob as well and no joy.
> 
> If anyone could see what I am missing it would be greatly appreciated!
> Thanks!

Case statement takes glob(7) pattern, not regular expression.  Well,
'extglob' is in the right direction.  Try

    case $1 in
	[+-]+([0-9]) ) echo "Match is $1" ;;
	* ) echo "No match." ;;
    esac
-- 
William
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