Batch rename sequential files by padding with zeroes

Question

I have a bunch of files named like so:

output_1.png
output_2.png
...
output_10.png
...
output_120.png

What is the easiest way of renaming t

Answer 1

Fairly easy, although it combines a few features not immediately obvious:

@echo off
setlocal enableextensions enabledelayedexpansion
rem iterate over all PNG files:
for %%f in (*.png) do (
    rem store file name without extension
    set FileName=%%~nf
    rem strip the "output_"
    set FileName=!FileName:output_=!
    rem Add leading zeroes:
    set FileName=000!FileName!
    rem Trim to only four digits, from the end
    set FileName=!FileName:~-4!
    rem Add "output_" and extension again
    set FileName=output_!FileName!%%~xf
    rem Rename the file
    rename "%%f" "!FileName!"
)

Edit: Misread that you're not after a batch file but any solution in any language. Sorry for that. To make up for it, a PowerShell one-liner:

gci *.png|%{rni $_ ('output_{0:0000}.png' -f +($_.basename-split'_')[1])}

Stick a ?{$_.basename-match'_\d+'} in there if you have other files that do not follow that pattern.

Answer 2

I actually just needed to do this on OSX. Here's the scripts I created for it - single line!

> for i in output_*.png;do mv $i `printf output_%04d.png $(echo $i | sed 's/[^0-9]*//g')`; done

Answer 3

Here is a Python script I wrote that pads zeroes depending on the largest number present and ignores non-numbered files in the given directory. Usage:

python ensure_zero_padding_in_numbering_of_files.py /path/to/directory

Body of script:

import argparse
import os
import re
import sys

def main(cmdline):

    parser = argparse.ArgumentParser(
        description='Ensure zero padding in numbering of files.')
    parser.add_argument('path', type=str,
        help='path to the directory containing the files')
    args = parser.parse_args()
    path = args.path

    numbered = re.compile(r'(.*?)(\d+)\.(.*)')

    numbered_fnames = [fname for fname in os.listdir(path)
                       if numbered.search(fname)]

    max_digits = max(len(numbered.search(fname).group(2))
                     for fname in numbered_fnames)

    for fname in numbered_fnames:
        _, prefix, num, ext, _  = numbered.split(fname, maxsplit=1)
        num = num.zfill(max_digits)
        new_fname = "{}{}.{}".format(prefix, num, ext)
        if fname != new_fname:
            os.rename(os.path.join(path, fname), os.path.join(path, new_fname))
            print "Renamed {} to {}".format(fname, new_fname)
        else:
            print "{} seems fine".format(fname)

if __name__ == "__main__":
    sys.exit(main(sys.argv[1:]))

Answer 4

For mass renaming the only safe solution is mmv—it checks for collisions and allows renaming in chains and cycles, something that is beyond most scripts. Unfortunately, zero padding it ain't too hot at. A flavour:

c:> mmv output_[0-9].png output_000#1.png

Here's one workaround:

c:> type file
mmv
[^0-9][0-9] #1\00#2
[^0-9][0-9][^0-9] #1\00#2#3
[^0-9][0-9][0-9] #1\0#2#3
[^0-9][0-9][0-9][^0-9] #1\0#2#3
c:> mmv <file

Answer 5

Using ls + awk + sh:

ls -1 | awk -F_ '{printf "%s%04d.png\n", "mv "$0" "$1"_", $2}' | sh

If you want to test the command before runing it just remove the | sh

Answer 6

Python

import os
path = '/path/to/files/'
for filename in os.listdir(path):
    prefix, num = filename[:-4].split('_')
    num = num.zfill(4)
    new_filename = prefix + "_" + num + ".png"
    os.rename(os.path.join(path, filename), os.path.join(path, new_filename))

you could compile a list of valid filenames assuming that all files that start with "output_" and end with ".png" are valid files:

l = [(x, "output" + x[7:-4].zfill(4) + ".png") for x in os.listdir(path) if x.startswith("output_") and x.endswith(".png")]

for oldname, newname in l:
    os.rename(os.path.join(path,oldname), os.path.join(path,newname))

---

Bash

(from: http://www.walkingrandomly.com/?p=2850)

In other words I replace file1.png with file001.png and file20.png with file020.png and so on. Here’s how to do that in bash

#!/bin/bash
num=`expr match "$1" '[^0-9]*\([0-9]\+\).*'`
paddednum=`printf "%03d" $num`
echo ${1/$num/$paddednum}

Save the above to a file called zeropad.sh and then do the following command to make it executable

chmod +x ./zeropad.sh

You can then use the zeropad.sh script as follows

./zeropad.sh frame1.png

which will return the result

frame001.png

All that remains is to use this script to rename all of the .png files in the current directory such that they are zeropadded.

for i in *.png;do mv $i `./zeropad.sh $i`; done

---

Perl

(from: Zero pad rename e.g. Image (2).jpg -> Image (002).jpg)

use strict;
use warnings;
use File::Find;

sub pad_left {
   my $num = shift;

   if ($num < 10) {
      $num = "00$num";
   }
   elsif ($num < 100) {
      $num = "0$num";
   }

   return $num;
}

sub new_name {
   if (/\.jpg$/) {
      my $name = $File::Find::name;
      my $new_name;
      ($new_name = $name) =~ s/^(.+\/[\w ]+\()(\d+)\)/$1 . &pad_left($2) .')'/e;
      rename($name, $new_name);
      print "$name --> $new_name\n";
   }
}

chomp(my $localdir = `pwd`);# invoke the script in the parent-directory of the
                            # image-containing sub-directories

find(\&new_name, $localdir);

---

Rename

Also from above answer:

rename 's/\d+/sprintf("%04d",$&)/e' *.png