Re: case modification won't work with pattern

[Chet Ramey]

On 3/10/11 9:04 PM, Clark J. Wang wrote:
> On Thu, Mar 10, 2011 at 9:31 PM, Greg Wooledge <wooledg@eeg.ccf.org> wrote:
> 
>> On Thu, Mar 10, 2011 at 10:22:12AM +0800, Jerry Wang wrote:
>>>       var="abcabc"
>>>       echo "var: ${var}"
>>>       echo "replace the leading \"ab\" to uppercase: ${var^ab}" # expect
>> to get "ABcabc" ?
>>
>> The documentation is a bit terse, admittedly.
> 
> 
> Agree. Almost all of the poeple around me don't understand why it works that
> way. Maybe some background of the feature requirement can help us to
> understand better.

The original requests were for a way to change the first letter or
every letter to uppercase or lowercase, like ksh typeset -l/-u, using
word expansion syntax (one request was for a new builtin command to
do it).  That's what you get if you don't use the pattern part of the
expansion.  I invented the pattern following the case specifier to allow
each character to be separately modified.

Chet
-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU    chet@case.edu    http://cnswww.cns.cwru.edu/~chet/