Zero-pad numbers in file names that are not padded

Question

I have a directory full of files named

image_1.jpg
image_2.jpg
...
image_10.jpg
...
image_335.jpg

Now I want to use a command line tool which expects the images to be alphabetical ordered. But the alphabetical order of these filenames is: image_100.jpg image_101.jpg ... image_10.jpg image_11.jpg ... image_1.jpg ....

How can I rename these files using a short shell / bash command? I've found that sed is possible a way to go, but this tool is a mystery to me.

Maybe your tool just uses the order given? For example, if you invoke it as `sometool image*.jpg` then you can just do `sometool image_{1..335}.jpg` instead. — that other guy, Aug 24 '15 at 15:15
http://stackoverflow.com/questions/9896070/pad-numerical-values-in-filename-with-three-digit-value-using-sed — bishop, Aug 24 '15 at 15:24
@thatotherguy no the tool simply expects the working dir to be full of ordered images :( — sweiler, Aug 24 '15 at 15:31
Which OS are you doing this on? Do you have a `rename` command? — that other guy, Aug 24 '15 at 17:23
`ls -v *` may be your friend but using `ls` to pass file names is always fraught with othe problems. — potong, Aug 25 '15 at 05:34

Cyrus · Accepted Answer · 2015-08-24T16:42:01.280

With bash:

for i in *; do if [[ $i =~ (image_)([0-9]{1,2})(\.jpg) ]]; then printf -v num "%03d" "${BASH_REMATCH[2]}"; echo mv -v "$i" "${BASH_REMATCH[1]}${num}${BASH_REMATCH[3]}"; fi; done

If everything looks okay, remove echo.

Tested with a directory with those file names:

image_100.jpg
image_101.jpg
image_10.jpg
image_11.jpg
image_1.jpg
image_2.jpg
image_334.jpg
image_335.jpg
image_3.jpg

The created commands:

mv -v image_10.jpg image_010.jpg
mv -v image_11.jpg image_011.jpg
mv -v image_1.jpg image_001.jpg
mv -v image_2.jpg image_002.jpg
mv -v image_3.jpg image_003.jpg

Result:

image_001.jpg
image_002.jpg
image_003.jpg
image_010.jpg
image_011.jpg
image_100.jpg
image_101.jpg
image_334.jpg
image_335.jpg

score 0 · Answer 2 · answered Aug 24 '15 at 15:30

Ok I've found a solution, not using a shell command but by writing a simple ruby script:

input = Dir.glob("image*.jpg")

input.each do |name|
  parts = name.split /[_\.]/
  number = parts[1]
  number = number.rjust(3, '0')
  new_name = [parts[0], '_', number, '.', parts[2]].join
  File.rename(name, new_name)
end

Zero-pad numbers in file names that are not padded

2 Answers2