Re: how do I write a shell script to batch rename files in a directory?

[Bob Proulx]

Tony Zanella wrote:
> I have a directory listing of files like:
> img.bc03.547.1.gif?
> I need to trim the last character off for each file in the dir.
> I know I can use:
> mv img.bc03.547.1.gif? img.bc03.547.1.gif
> to rename each by hand, but I want to do this as a batch.
> I know it would start with:
> for files in *; do;
> after that, I'm stuck!
> Any suggestions?

The easiest way is to use the 'rename' command which is usually
installed as part of Perl.

  rename --verbose 's/.gif\?$/.gif/' *.gif?

But bash can of course be used to write a small command line program
to do this too.  Here is one way (there are many):

  for i in *.gif?; do mv --verbose $i ${i%\?}; done

See the bash manual section "Parameter Expansion" for more information
on doing bash substitution.

       ${parameter%word}
       ${parameter%%word}
              The  word  is  expanded to produce a pattern just as in pathname
              expansion.  If the pattern matches a  trailing  portion  of  the
              expanded value of parameter, then the result of the expansion is
              the expanded value of parameter with the shortest matching  pat-
              tern  (the  ‘‘%’’  case)  or  the  longest matching pattern (the
              ‘‘%%’’ case) deleted.  If parameter  is  @  or  *,  the  pattern
              removal  operation  is  applied  to each positional parameter in
              turn, and the expansion is the resultant list.  If parameter  is
              an  array  variable subscripted with @ or *, the pattern removal
              operation is applied to each member of the array  in  turn,  and
              the expansion is the resultant list.

Bob