case command and regex

[Daniel Wayne Armstrong]

On Sat, Mar 16, 2013 at 10:53 PM, William Park <opengeometry-FFYn/CNdgSA at public.gmane.org> wrote:
> 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

Thanks William and Chris! The point about globbing narrowed my search and:

shopt -s extglob

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

... indeed works as desired. I was jumbling up the regex and globbing
earlier ... the manpage was a help as well as this LJ article:

http://www.linuxjournal.com/content/bash-extended-globbing

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