Re: how to rename multiple files

[Mark Zimmerman <mark@foresthaven.com>]

On Sat, Jan 04, 2003 at 07:00:03PM -0600, Gerald V. Livingston II wrote:
> Colin Watson said:
> 
> > On Tue, Dec 10, 2002 at 11:20:31AM -0800, Osamu Aoki wrote:
> >> if [ -e *.JPG ]; then for i in *.JPG; do mv "$i" "${i%.JPG}.jpg";
> >> done fi
> >
> > That -e test looks dreadful ... surely it'll usually expand to lots of
> > arguments which will confuse [, or perhaps to an empty string
> > (nullglob)
> > which will also confuse test?
> >
> > --
> > Colin Watson
> > [cjwatson@flatline.org.uk]
> 
> And I've bumped into this. How *DOES* one test for the existence of
> ANY file with a given extension without getting a "too many arguments"
> error when there are multiple files?
> 
> I want "TRUE" if there is one or more zzz.jpg files in a directory,
> "FALSE" if there are zero of them.
> 

This is icky but works:

shopt -s nullglob
SOME=FALSE
MATCH=*.jpg
for f in $MATCH; do SOME=TRUE; break; done

I tried [ -z $MATCH ] also but it always fails even though echo $MATCH
prints an empty string.

-- Mark