find with -print0

October 13, 2021

I like using find with xargs and perl to do find-and-replace. Like this:

$> find . -type f | xargs perl -p -i -e "s/old_string/new_string"

This works great, until you have filenames with spaces in them. Because xargs usually splits on newlines and/or spaces, a filename with a space will appear to xargs as two files:

$> ls -l find_test
total 16
-rw-r--r--  1 alextaylor  staff  11 13 Oct 15:17 I have spaces
-rw-r--r--  1 alextaylor  staff  11 13 Oct 15:18 i_have_underscores

$> find find_test/ -type f | xargs perl -p -i -e "s/old_string/new_string/"
Can't open find_test//I: No such file or directory, <> line 1.
Can't open have: No such file or directory, <> line 1.
Can't open spaces: No such file or directory, <> line 1.

What to do?

-print0 to the rescue

Using find’s -print0 option will separate filenames with a null character, and xargs has a complementary -0 character that will interpret these:

$> find find_test/ -type f -print0 | xargs -0 perl -p -i -e "s/old_string/new_string/"

# nothing to show... it worked!