A simple perl script to enable bulk renaming of files.

rename.pl

#!/usr/bin/env perl

# RN
#
# `rn` is a bulk renaming script for the Linux filesystem.  It takes a
# single transformation argument followed by a list of filenames.  The
# transformation argument must be a perl expression, but most of the
# time that amounts to a simple regular expression.
#
# Examples:
#
# $ rn 's/\.jpeg$/.jpg/' *.jpeg                 ; converts all files ending in 'jpeg' to 'jpg' in the current folder.
# $ rn 's/\.bak$//' *.bak                       ; remove the '\.bak' extension from all files in the current folder.
# $ rn 'printf("%02d_%s", "$.", "$_")' *.txt    ; give every file endind in 'txt' with a two-digit prefix in ascending order.
#

($op = shift) || die "Usage: $0 perlexpr [filenames]\n";

if (!@ARGV) {
    @ARGV = <STDIN>;
    chomp(@ARGV);
}

foreach (@ARGV) {
    $was = $_;
    eval $op;
    die $@ if $@;
    if (-e $_) {
        print "wont overwrite existing $_ with $was\n";
        next;
    }
    $ok = rename($was, $_) unless ($was eq $_);
    $ok or print STDERR "fail rename($was, $_): $!\n";
}