Search and replace string in file names without affecting folder names which contains same string - linux

Question

I have a folder which contains multiple subfolders and files with different names.
I want to change file names which contains specific string with a new name. It works when the string i want to change is not same with subfolder names. When it does my code is failing.
Example directory and files:
./cat/cat_1.py
./cat/small_cat_2.py
./small_cat_3.py
./example/cat_4_small.py
My working command:
find -name '*small*' -type f -exec bash -c 'mv "$0" "${0/small/${1}}"' {} ${NEW_NAME} \;
It works without problem.
My failing command:
find -name '*cat*' -type f -exec bash -c 'mv "$0" "${0/cat/${1}}"' {} ${NEW_NAME} \;
For NEW_NAME=dog
It doesn't work because this command tries to replace folder names from ./cat/cat_1.py as ./dog/dog_1.py which is a situation I don't want.
I want to rename ./cat/cat_1.py as ./cat/dog_1.py.
I set NEW_NAME parameter with user input.
Folders and files are not static, it is changing every day so i can't change my working directory to "cat" folder and make replacement in cat subfolders statically.
Every day new directories and files may be created. So my code have to handle new situations.
Can anyone help about it?

Answer 1

You need a different shell script to process the renames.
Since you want to rename only the base name of the file and not the directory path basedir of it, you will have to split the basename from the basedir,
then perform the rename:
#!/usr/bin/env bash
# Capture the replacement name as the first argument
newname="$1"
# Shift the first argument out of the argument array
shift
# Iterate the remaining arguments files paths provided by the find command
for filepath; do
# Capture the base file name of the file path
# by stripping out all leading characters up to and including the last /
basename=${filepath##*/}
# Capture the base directory of the file path
# by stripping out all the trailing characters starting at
# and including the last /
basedir=${filepath%/*}
# Perform the replacement of the cat string with the newname
# within the old base name of the file to build its new base name
newbasename=${basename/cat/"$newname"}
# Proceed to the renames, of the old filename path to the
# reassembled base directory with the new base name
echo mv -- "$filepath" "$basedir/$newbasename"
done
With the inline bash inside find:
find . -name '*cat*' -type f -exec bash -c 'r=$1;shift;for p;do o=${p##*/};d=${p%/*};echo mv -- "$p" "$d/${o/cat/"$r"}";done' _ dog {} \+;
If satisfied by the output, remove the echo so it executes the command, or pipe the output to a shell.