Add number 20 to folder names and (-) between sections

Question

He guys I have folders listed as 230101 230102 230103 - infinite daily made I need a way in bash or batch to re name the folders to 2023-01-01 as example But I need it to be automated So the issue is we need to add number 20 In beginning of the folder name and two - to every folder Any suggestions?

I have tried to make the name of the files as variable I kept getting a lot of errors so I need someone to guide me please.

Answer 1

You can use the loop that creates new_dir names from sub-strings of dir names. The ??????/ glob is used to match only directories with 6-character names:

#!/bin/bash

for dir in ??????/; do
  dir=${dir%/}
  new_dir="20${dir:0:2}-${dir:2:2}-${dir:4:2}"
  if [ -d "$new_dir" ]; then
    mv -n "${dir}"/* "$new_dir"/
    rmdir "${dir}"
  else
    mv "$dir" "$new_dir"
  fi
done