How to “search and replace” many files?

Question

I use the grep command to search for a string in many files. Is there something similar to "search and replace"?

Answer 1

You are looking for the sed command. For example, to replace the "dog" with "cat" in all text files in the current directory:

sed -i 's/dog/cat/' *.txt

Answer 2

sed comes to mind. Example:

sed s/cat/dog/ <input >output

This searches for cat in a line and puts dog on it's place in the file input and writes to file output.

Answer 3

sed is the right tool; but, as an alternative, you can even use ex commands in vim:

vim -c 'args <files> | argdo %s/cat/dog/g | x'

where <files> is the list of files or patterns in which you want to make the substitution.