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Accepted
Joe Cola
Asked: 2020-07-16 03:33:57 +0800 CST

How to enumerate a variable in a loop starting at 01?

  • 772

I have a question

I have the rename command, but after I run the rename starting from 00, how to start from 01, please help me

this is the command that I use

for i in *.mkv; do
  new=$(printf "Movie - %02d.mkv" "$a")
  mv -i -- "$i" "$new"
  let a=a+1
done
programming command-line gnome-terminal bash rename

2 Answers

  1. Best Answer

    Simple as adding a variable (a=1) at the beginning:

    #!/bin/bash
a=1
for i in *.mkv; do
  new=$(printf "Movie - %02d.mkv" "$a")
  mv -i -- "$i" "$new"
  let a=a+1
done

    Here is in one line as you asked for:

    a=1; for i in *.mkv; do new=$(printf "Movie - %02d.mkv" "$a"); mv -i -- "$i" "$new"; let a=a+1; done
    • 2

  2. The same can be done with bash's arithmetic evaluation, too. And it's generally preferred over let builtin.

    For exmaple,

    #!/bin/bash

a=1
for i in *.mkv; do
  new=$(printf "Movie - %02d.mkv" "$a")
  mv -i -- "$i" "$new"
  ((a++))
done

    On other hand, if you prefer a one-liner, rename command can do that:

    rename 's/\d+/sprintf("Movie - %02d", $&)/e' *.mkv
    • 1