How to decrease number in filename list by sed or similar tool

Question

I have a list of files numbered in the filename, starting eg. at 013 (or another count) but want them renamed to start by 001. I don't mind the tool used (awk, sed, mv, tr, what-ever...)

Example (before -> after):

img013.tif -> img001.tif
img014.tif -> img002.tif
...

etc.

Appreciate any help. 1000 x thanks, Roland

Answer 1

Since a glob expression will retrieve the file list in alphabetical (alphanumerical) order you can simply use this:

#!/bin/bash

i=0
# The loop iterates over tif files in alphanumerical order
for file in *.tif ; do
    mv -v "$file" "img$(printf "%03d" "$i").tif"
    i=$((i+1))
done