How to batch rename files using loop combination in bash?

Question

I have 2 folder structure like this:

SOURCE_FOLDER_W_GOOD_NAMES
├── A_some_name.png
├── B_another_different_name.png
├── C_just_another_too.png
└── D_this_one_stop_this_example.png

Another folder:

DESTINATION_FOLDER_W_INCREMENT_NAMES
├── icon_0.icns
├── icon_1.icns
├── icon_2.icns
└── icon_3.icns

So basically, SOURCE_FOLDER already contains the files which are sorted in alphabetical order. This sort order is already matched with DESTINATION_FOLDER (eg: A_some_name.png === icon_0.icns)

I'm using this loop combination to rename the files:

i=0
j=0
for img in SOURCE_FOLDER/*.png; do
  for i in {0..10000}; do
    let j++ || true;
    mv "SOURCE_FOLDER/icon_$i.icns" "DESTINATION_FOLDER/${img%.*}.icns"
  done
done

I executed this on the command line (the above is formatted, I'm a one-liner guy) in the root of the above folder.

THE_FATHER_FOLDER
├── SOURCE_FOLDER_W_GOOD_NAMES
└── DESTINATION_FOLDER_W_INCREMENT_NAMES

Unfortunately, the above loop is not working as I expected. I'm certain that I'm wrong but I don't know where.

Please correct me.

UPDATED

Solution for the above question, I solved it myself

counter=0
for img in SOURCE_FOLDER/*.png; do
  let counter++ || true;
  mv "SOURCE_FOLDER/icon_$counter.icns" "DESTINATION_FOLDER/${img%.*}.icns"
done

But I have another question, in this folder:

DESTINATION_FOLDER_W_INCREMENT_NAMES
├── icon_0.icns
├── icon_1.icns
├── icon_2.icns
└── icon_3.icns

I want to reindex it from 1 instead of 0, thus I'm using this:

counter=0
for index in {0..final_number}; do
  let counter++ || true;
  mv "icon_${index}.icns" "icon_${counter}.icns";
done

At the moment, my files are started from 0 and ended up by final_number - 1, so it will overwrite every single-file I have in this folder and I got only the first file (icon_0) which renamed to (icon_final_number) when it's done.

How could I resolve this?

Answer 1

You want to do the rename backwards:

counter=$((final_number + 1))
for index in {final_number..0}; do
  mv "icon_${index}.icns" "icon_${counter}.icns";
  let counter--;
done

Answer 2

Your problems will be solved by the following code:

#!/bin/sh

i=0
for img in `ls SOURCE_FOLDER_W_GOOD_NAMES/*.png`; do
        mv $img DESTINATION_FOLDER_W_INCREMENT_NAMES/icon_$i.icns
        i=$((i+1));
done

Answer 3

Initialize your counter with the value 1 instead of 0, and increase it after a move is done. Then you won't need to run a secondary bash script just for renaming the files, you would address it in the original script.

Also, why when you increase your counter you add " || true" ? it has no meaning. Try this code

counter=1
for img in SOURCE_FOLDER/*.png; do
  mv "SOURCE_FOLDER/icon_$counter.icns" "DESTINATION_FOLDER/${img%.*}.icns"
  let counter++
done