bash script rename multiple files [duplicate]

Answer 1

If your system has rename tool, it's better to go with the simple rename command,

rename 's/^.{5}//' *.nai

It just remove the first 5 characters from the file name.

OR

for i in *.nai; do mv "$i" $(grep -oP '(?<=^.{5}).+' <<< "$i"); done

Answer 2

You would be better off using rename (prename on some systems) since that allows you to use Perl regular expressions to do the renaming, along the lines of:

prename 's/^.{5}//' *.nai

The reason your script is not behaving is that, for every source file, you're attempting to rename it to every target file.

If you need to limit yourself to using that script, you need to work out the single target file for each source file, something like:

#!/bin/bash
for i in *.nai; do
    y=$(echo "$i" | cut -c6-)
    mv "$i" "$y"
done

Answer 3

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.

Answer 4

Using only bash, you could do this:

for file in *nai* ; do
  echo mv -- "$file" "${file:5}"
done

_{(Remove the echo when satisfied with the output.)}

Avoid ls in scripts, except for displaying information. Use plain globbing instead.

See also How do I do string manipulations in bash? for more string manipulation techniques.

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Your script can't work with that structure: if you have 5 files, it will call mv five times for the first file (once for each element in the second list), five times for the second, etc. You'd need to iterate over the two sets of names in lockstep. (It also doesn't deal with things like whitespace in filenames.)