Converts digits from 00-99 or 0-9 to 000-099, of any files, in a directory tree.

3digits.pl

#!/usr/bin/perl -w

use File::Copy;
use Cwd;

# a simple rename scheme for the files.
sub add0 {
    move($_[0], "$_[1]$_[0]");
}

# check the files that will be renamed.
sub checkFile {
    add0($_, "00") and ++$value if ($_ =~ m/^[0-9]\..*/);
    add0($_, "0") and ++$value if ($_ =~ m/^[0-9]{2}\..*/);
}

@dirTree;
$value = 0;

opendir(DIR, getcwd()) or die $!;
# read directory for both files and if it is a directory tree
while (readdir(DIR)) {
    push(@dirTree, $_) if (-d $_ and $_ =~ m/^[^\.*]/);
    checkFile($_);
}

# check the dirtree for all the files
foreach my $dir (@dirTree) {
    opendir(TMP, $dir) or die "ERROR on directory $dir.\n $!";

    # need to chdir since no file would be found otherwise.
    chdir(TMP) and print("Entered: $dir directory\n");

    # check current directory and rename the files if files exist.
    checkFile($_) while (readdir(TMP));

    # close the TMP directory and chdir back to DIR.
    closedir(TMP);
    chdir(DIR);
}

closedir(DIR);
print("changed $value files\n");