Re: [Help-bash] How to extract matching suffix pattern in bash?

[Eric Blake]

On 03/13/2013 08:04 PM, Chet Ramey wrote:
> On 3/13/13 6:21 PM, Peng Yu wrote:
>> Hi,
>>
>> ${parameter%word} remove matching suffix pattern. I need something
>> extract only the matching suffix which is to be not available
>> according to bash manual. Do I miss anything?
> 
> This is totally untested, but should be fairly self-explanatory, and is
> portable to any Posix shell:
> 
> suffix_pattern=whatever
> prefix=${string%$suffix_pattern}
> suffix=${string##$prefix}

Except that it isn't robust if pattern contains globs:

$ foo='a.*b'
$ prefix=${foo%b}
$ suffix=${foo##$prefix}
$ echo "$suffix"

$ echo "$prefix"
a.*

A more robust solution might involve counting the length of prefix,
creating a string consisting of that many '.', and chopping off that
that instead of risking expansion of the prefix turning into an
unexpected glob match.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

signature.asc
Description: OpenPGP digital signature