Friday, May 20, 2011

Rename Perl script on the Mac

I love Linux and BSD. I also love my Mac. I really like the user interface, and the underlying BSD roots. (Insert generic Mac fan-pitch)

There are a few things which drive me NUTS about the BSD underpinnings of the Mac, though. MacPorts is a great step in the direction of bringing better Linux/BSD program onto the Mac platform, but it doesn't always have everything you need (And it's pretty slow). The most recent annoyance is the lack of the 'rename' linux command, my favorite of which enables me to bulk rename files based on a regular expression. Yes, I could hack together an awk or bash script to do this each time, but (like Matt), I like simpler == better.

So, when I ran into this issue yesterday, I decided I had enough. It turns out that the rename linux command that I like (based on regular expressions, not some other more simplistic syntax shipped with Redhat) is just a perl script.

So, I found the script on one of my Ubuntu servers (prename), slapped it into /usr/local/bin, and away I went. Much easier than some other custom compiling Mac solutions.

(Sorry for the lame code posting...blogspot sucks with that...or I suck finding a better way!)

#!/usr/bin/perl -w
#  This script was developed by Robin Barker (,
#  from Larry Wall's original script eg/rename from the perl source.
#  This script is free software; you can redistribute it and/or modify it
#  under the same terms as Perl itself.
# Larry(?)'s RCS header:
#  RCSfile: rename,v   Revision: 4.1   Date: 92/08/07 17:20:30 
# $RCSfile: rename,v $$Revision: 1.5 $$Date: 1998/12/18 16:16:31 $
# $Log: rename,v $
# Revision 1.5  1998/12/18 16:16:31  rmb1
# moved to perl/source
# changed man documentation to POD
# Revision 1.4  1997/02/27  17:19:26  rmb1
# corrected usage string
# Revision 1.3  1997/02/27  16:39:07  rmb1
# added -v
# Revision 1.2  1997/02/27  16:15:40  rmb1
# *** empty log message ***
# Revision 1.1  1997/02/27  15:48:51  rmb1
# Initial revision

use strict;

use Getopt::Long;

my ($verbose, $no_act, $force, $op);

die "Usage: rename [-v] [-n] [-f] perlexpr [filenames]\n"
unless GetOptions(
'v|verbose' => \$verbose,
'n|no-act'  => \$no_act,
'f|force'   => \$force,
) and $op = shift;

$verbose++ if $no_act;

if (!@ARGV) {
print "reading filenames from STDIN\n" if $verbose;
@ARGV = ;

for (@ARGV) {
my $was = $_;
eval $op;
die $@ if $@;
next if $was eq $_; # ignore quietly
if (-e $_ and !$force)
warn  "$was not renamed: $_ already exists\n";
elsif ($no_act or rename $was, $_)
print "$was renamed as $_\n" if $verbose;
warn  "Can't rename $was $_: $!\n";


=head1 NAME

rename - renames multiple files


B S<[ B<-v> ]> S<[ B<-n> ]> S<[ B<-f> ]> I S<[ I ]>


renames the filenames supplied according to the rule specified as the
first argument.
The I 
argument is a Perl expression which is expected to modify the C<$_>
string in Perl for at least some of the filenames specified.
If a given filename is not modified by the expression, it will not be
If no filenames are given on the command line, filenames will be read
via standard input.

For example, to rename all files matching C<*.bak> to strip the extension,
you might say

rename 's/\.bak$//' *.bak

To translate uppercase names to lower, you'd use

rename 'y/A-Z/a-z/' *

=head1 OPTIONS

=over 8

=item B<-v>, B<--verbose>

Verbose: print names of files successfully renamed.

=item B<-n>, B<--no-act>

No Action: show what files would have been renamed.

=item B<-f>, B<--force>

Force: overwrite existing files.



No environment variables are used.

=head1 AUTHOR

Larry Wall

=head1 SEE ALSO

mv(1), perl(1)


If you give an invalid Perl expression you'll get a syntax error.

=head1 BUGS

The original C did not check for the existence of target filenames,
so had to be used with care.  I hope I've fixed that (Robin Barker).


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