Find and replace filename recursively in a directory

I want to rename all the files in a folder which starts with 123_xxx.txt to xxx.txt.

For example, my directory has:

123_xxx.txt
123_yyy.txt
123_zzz.txt

I want to rename all files as:

xxx.txt
yyy.txt
zzz.txt

I have seen some useful bash scripts in this forum but I'm still confused how to use it for my requirement.

Let us suppose I use:

for file in `find -name '123_*.txt'` ; do mv $file {?.txt} ; done

Is this the correct way to do it?

Solution

You can do it this way:

find . -name '123_*.txt' -type f -exec sh -c '
for f; do
    mv "$f" "${f%/*}/${f##*/123_}"
done' sh {} +

No pipes, no reads, no chance of breaking on malformed filenames, no non-standard tools or features.