rename multiple files with regular-expression - bash

Question

Inside a folder I have a file structure, the files have all a name whose format
name-randomstring.extension
eg
./dir1/aaa-5h34jk5hk.js
./dir2/bbb-5yh45uh9h.css
./dir3/ccc-uiero6tio.js
./dir3/ddd-7y8fygfre.css
. . .
with a bash script I would like to rename them recursively; so to eliminate the -randomstring from every file
./dir1/aaa.js
./dir2/bbb.css
./dir3/ccc.js
./dir3/ddd.css
. . .

Answer 1

You can do this with a native bash loop:
shopt -s globstar # enable ** for recursive expansion
for file in **/*{j,cs}; do
# remove everything up to the last . to get extension
ext=${file##*.}
# remove everything after the last - and concat with extension
new_name=${file%-*}$ext
# -- prevents weird filenames being interpreted as options
mv -- "$file" "$new_name"
done
shopt -u globstar # disable ** if you don't want it anymore e.g. in a script

Answer 2

if you do not mind using Perl then you can do anything you like.
for example for renaming all files with this structure:
dir > find .
.
./00_file.txt
./01_file.txt
./02_file.txt
./dir1
./dir1/00_file.txt
./dir1/01_file.txt
./dir1/02_file.txt
./dir2
./dir2/00_file.txt
./dir2/01_file.txt
./dir2/02_file.txt
./dir3
./dir3/00_file.txt
./dir3/01_file.txt
./dir3/02_file.txt
./find.log
then save your list in a file like: find.log now you can use Perl
dir > perl -lne '-f && ($old=$_) && s/file/ABCD/g && print "$old => $_"' find.log
./00_file.txt => ./00_ABCD.txt
./01_file.txt => ./01_ABCD.txt
./02_file.txt => ./02_ABCD.txt
./dir1/00_file.txt => ./dir1/00_ABCD.txt
./dir1/01_file.txt => ./dir1/01_ABCD.txt
./dir1/02_file.txt => ./dir1/02_ABCD.txt
./dir2/00_file.txt => ./dir2/00_ABCD.txt
./dir2/01_file.txt => ./dir2/01_ABCD.txt
./dir2/02_file.txt => ./dir2/02_ABCD.txt
./dir3/00_file.txt => ./dir3/00_ABCD.txt
./dir3/01_file.txt => ./dir3/01_ABCD.txt
./dir3/02_file.txt => ./dir3/02_ABCD.txt
how it works?
read the file
let only file; not directory or other stuffs with: -f
then save the old name: ($old=$_)
then doing substitution with: s///g operator
finally rename the old file to new one that is $_
NOTE I used print and you should use rename like this:
dir > perl -lne '-f && ($old=$_) && s/file/ABCD/g && rename $old, $_' find.log
dir > find .
.
./00_ABCD.txt
./01_ABCD.txt
./02_ABCD.txt
./dir1
./dir1/00_ABCD.txt
./dir1/01_ABCD.txt
./dir1/02_ABCD.txt
./dir2
./dir2/00_ABCD.txt
./dir2/01_ABCD.txt
./dir2/02_ABCD.txt
./dir3
./dir3/00_ABCD.txt
./dir3/01_ABCD.txt
./dir3/02_ABCD.txt
./find.log
NOTE Since the find returns list of all files and sub-directories, with this technique Perl renames all the files! Thus first use print then rename. And your pattern can be: -.*(?=\.). In fact:
s/-.*(?=\.)//g