How to replace one char with another in all filenames of the current directories?

Question

How do you rename all files/subdirs in the current folder?

Lets say, I have many files and subdirs that are with spaces and I want to replace all the spaces with an underscore.

File 1
File 2
File 3
Dir 1
Dir 3

should be renamed to

File_1
File_2
File_3
Dir_1
Dir_3

Answer 1

If you need to rename files in subdirectories as well, and your find supports the -execdir predicate, then you can do

find /search/path -depth -name '* *' \
    -execdir bash -c 'mv -- "$1" "${1// /_}"' bash {} \;

Thank to @glenn jackman for suggesting -depth option for find and to make me think.

Note that on some systems (including GNU/Linux ones), find may fail to find files whose name contains spaces and also sequences of bytes that don't form valid characters (typical with media files with names with non-ASCII characters encoded in a charset different from the locale's). Setting the locale to C (as in LC_ALL=C find...) would address the problem.

Answer 2

In any shell, you can loop over the files whose name contains a space. Replacing the spaces with underscores is easy in bash, ksh and zsh with the ${VARIABLE//PATTERN/REPLACEMENT} construct.

for x in *" "*; do
  mv -- "$x" "${x// /_}"
done

On Debian, Ubuntu and derivatives, you can use the Perl rename (other distributions ship a different program as rename, and that program isn't helpful here).

rename 's/ /_/g' *

An obligatory zsh solution:

autoload zmv
zmv '(*)' '${1// /_}'

An obligatory POSIX solution:

for x in *" "*; do
  y=$(printf %sa "$x" | tr " " "_")
  mv -- "$x" "${y%a}"
done

Answer 3

You can use rename for this (here assuming the one from util-linux, not the perl one):

cd /path/to/dir
rename ' ' _ *\ *

This will find all files and directories space in the name and replace the space with an underscore. Since it uses glob file matching you need to be in the right directory to start with.

If you want to do recursive matches you can, but you might have to execute the rename a couple times to catch any items in directories that themselves got renamed:

cd /path/to/dir
shopt -s globstar
rename ' ' _ **/*\ *
!!; !!

Answer 4

Another option would be mmv, if installed.

mmv \*\ \* \#1_#2

Answer 5

On Debian/Ubuntu, building upon the answers of Caleb and Gilles, this is what worked for me to rename files recursively:

cd /path/to/dir
shopt -s globstar
rename 's/ /_/g' **

Note: To preview what files would be renamed and how, use the -n switch with rename:

rename -n 's/ /_/g' **

Another note: setting globstar makes ** match files in all subdirectories, so if only current directory is desired, don't set globstar or use * instead of **.

One more note: The rename command needs to be run more than once for files with multiple occurrences of the search term.

Answer 6

If you're not a flash at regular expressions (I'm not!), and you can run applications designed for kde (either you use kde - k desktop or you have it's libraries installed), then krename is a great graphical utility that lets you see the before and after before you commit to the changes. It has a number of simple transformations as options and also supports regular expressions. You can even combine several sequential transformations into one rename so you don't have to design a single complex transform that does it all at once. It also has an option to continue renaming the same files after a rename has been applied.

I don't use it that often, but when I do, it really gets the job done quickly and easily. It really comes in handy when renaming various downloaded media files so you can manage them uniformly on your system. It helps to download the krename manual separately so you can refer to it while using the program.

http://www.krename.net/