bash script rename multiple files [duplicate]

Answer 1

This:

#!/bin/bash

shopt -s extglob nullglob
for file in *+([[:digit:]]).nai; do
    echo mv -nv -- "$file" "${file##+([^[:digit:]])}"
done

Remove the echo if you're happy with the mv commands.

Note. This solution does not assume that there are 5 leading characters to delete. It will delete all the leading non-numeric characters.