Sure, you can do this with your editor, but did you know you can quickly and easily replace a pattern of text from the command line?

Check out this excellent tip from Will Keleher:

git grep -l pattern | xargs gsed -ri 's|pat(tern)|\1s are birds|g'

• git grep -l: make sure we're only looking for files in our codebase (ag -l is another good option)
• xargs: allow running this with gsed -i
• gsed -i: edit files (default mac sed is bad, so gnu-sed is essential)
• gsed -r: use regular expression for the pattern to allow capture groups
• s|: the first character after the s is used as the delimiter. / is pretty consistently annoying because it's used in file paths & urls.
• gsed '...': the single quotes are important to avoid escapes
• 's|pat(tern)|\1s are birds|g': being able to easily use capture groups in a find and replace is amazing
• |g: replace this multiple times in a line

Source: Will Keleher's article on Bash Patterns