TIL how to use in-place sed on Mac.

I always thought I have to use the GNU tools version of sed for in-place sed, but I was wrong. Mac sed supports in-place editing as well.

sed -i '' '/pattern/d' ./infile

There is a caveat though:

Edit files in-place, saving backups with the specified extension. If a zero-length extension is given, no backup will be saved. It is not recommended to give a zero-length extension when in-place editing files, as you risk corruption or partial content in situations where disk space is exhausted, etc.

Replace all occurances of foo with bar in the file test.txt, without creating a backup of the file:

sed -i '' -e 's/foo/bar/g' test.txt