Command line: search and replace in all filenames matched by grep

Question

I'm trying to search and replace a string in all files matched by grep:

grep -n 'foo' * will give me output in the form:

[filename]:[line number]:[text] 

For each file returned by grep, I'd like to modify the file by replacing foo with bar.

Answer 1

This appears to be what you want, based on the example you gave:

sed -i 's/foo/bar/g' * 

It is not recursive (it will not descend into subdirectories). For a nice solution replacing in selected files throughout a tree I would use find:

find . -name '*.html' -print -exec sed -i.bak 's/foo/bar/g' {} \; 

The *.html is the expression that files must match, the .bak after the -i makes a copy of the original file, with a .bak extension (it can be any extension you like) and the g at the end of the sed expression tells sed to replace multiple copies on one line (rather than only the first one). The -print to find is a convenience to show which files were being matched. All this depends on the exact versions of these tools on your system.

Answer 2

Do you mean search and replace a string in all files matched by grep?

perl -p -i -e 's/oldstring/newstring/g' `grep -ril searchpattern *` 

Edit

Since this seems to be a fairly popular question thought I'd update.

Nowadays I mostly use ack-grep as it's more user-friendly. So the above command would be:

perl -p -i -e 's/old/new/g' `ack -l searchpattern` 

To handle whitespace in file names you can run:

ack --print0 -l searchpattern | xargs -0 perl -p -i -e 's/old/new/g' 

you can do more with ack-grep. Say you want to restrict the search to HTML files only:

ack --print0 --html -l searchpattern | xargs -0 perl -p -i -e 's/old/new/g' 

And if white space is not an issue it's even shorter:

perl -p -i -e 's/old/new/g' `ack -l --html searchpattern` perl -p -i -e 's/old/new/g' `ack -f --html` # will match all html files