Answer by Lewy for sed in-place flag that works both on Mac (BSD) and Linux

When on OSX, I always install GNU sed version via Homebrew, to avoid problems in scripts, because most scripts were written for GNU sed versions.

brew install gnu-sed --with-default-names

Then your BSD sed will be replaced by GNU sed.

Alternatively, you can install without default-names, but then:

• Change your PATH as instructed after installing gnu-sed
• Do check in your scripts to chose between gsed or sed depending on your system