How to find and replace all occurrences of a string recursively in a directory tree? [duplicate]

Using just grep and sed, how do I replace all occurrences of:

a.example.com

with

b.example.com

within a text file under the /home/user/ directory tree recursively finding and replacing all occurrences in all files in sub-directories as well.

Solution 1:

Try this:

find /home/user/ -type f | xargs sed -i  's/a\.example\.com/b.example.com/g'

In case you want to ignore dot directories

find . \( ! -regex '.*/\..*' \) -type f | xargs sed -i 's/a\.example\.com/b.example.com/g'

Edit: escaped dots in search expression

Solution 2:

Try this:

grep -rl 'SearchString' ./ | xargs sed -i 's/REPLACESTRING/WITHTHIS/g'

grep -rl will recursively search for the SEARCHSTRING in the directories ./ and will replace the strings using sed.

Ex:

Replacing a name TOM with JERRY using search string as SWATKATS in directory CARTOONNETWORK

grep -rl 'SWATKATS' CARTOONNETWORK/ | xargs sed -i 's/TOM/JERRY/g'

This will replace TOM with JERRY in all the files and subdirectories under CARTOONNETWORK wherever it finds the string SWATKATS.

Solution 3:

On macOS, none of the answers worked for me. I discovered that was due to differences in how sed works on macOS and other BSD systems compared to GNU.

In particular BSD sed takes the -i option but requires a suffix for the backup (but an empty suffix is permitted)

grep version from this answer.

grep -rl 'foo' ./ | LC_ALL=C xargs sed -i '' 's/foo/bar/g'

find version from this answer.

find . \( ! -regex '.*/\..*' \) -type f | LC_ALL=C xargs sed -i '' 's/foo/bar/g'

Don't omit the Regex to ignore . folders if you're in a Git repo. I realized that the hard way!

That LC_ALL=C option is to avoid getting sed: RE error: illegal byte sequence if sed finds a byte sequence that is not a valid UTF-8 character. That's another difference between BSD and GNU. Depending on the kind of files you are dealing with, you may not need it.

For some reason that is not clear to me, the grep version found more occurrences than the find one, which is why I recommend to use grep.