zero padding of file names

Question

I want to do zero-padding for names of files. what should I do if not all images exist like 1.JPEG doesn't exist or 99.JPEG or 110.JPEG ?

 $ for n in $(seq 9); do mv $n.JPEG 0$n.JPEG; done; mv: cannot stat ‘1.JPEG’: No such file or directory

I do not want to rename manually because order of videos are important.

This answer Renaming hundreds of files at once for proper sorting uses the Perl-based rename with a simple shell glob - that avoids having to generate filenames — steeldriver, Nov 10 '19 at 18:32
Use "if" to check if the file exists. for n in $(seq 9); do if [[ -f $n.JPEG ]]; then mv $n.JPEG 0$n.JPEG; fi done;. — Kulfy, Nov 10 '19 at 18:32

score 1 · Accepted Answer · answered Nov 10 '19 at 18:40

You can use if inside the loop to check if the file exists. And if it does, then only mv operation would take place.

for n in $(seq 9) 
do 
  if [[ -f $n.JPEG ]] 
  then 
       mv $n.JPEG 0$n.JPEG 
  fi 
done;

Or in one line:

for n in $(seq 9); do if [[ -f $n.JPEG ]]; then mv $n.JPEG 0$n.JPEG; fi done;

score 1 · Answer 2 · 2019-11-10T19:36:54.803

Using parameter expansion you can split the filename into name and extension, then glue them together with printf formatting

#!/bin/bash

for i in *; do
    mv $i $(printf %04d.%s\\n ${i/./ })
done

printf formatting:

${parameter/pattern/string}

Pattern substitution; parameter is expanded and the longest match of pattern against its value is replaced with string.

2 Answers2