[jandy]

Not OP, but one I came across yesterday was `date`.

Linux: `date -d '10 mins ago'` Mac: `date -v -10M`

There's loads of tiny differences like this. Often just old versions, and you can pull in the latest with `brew` or something.

[btschaegg]

Another one is GNU find assuming the current directory if omitted, while BSD find explicitely has to be told the directory to search in.

It's nothing complicated, but breaks many scripts if you only test them on Linux (more or less the same problem like case-insensitive filesystems).

I'll have to add, though, that one could argue that OSX is the one behaving like "traditional UNIX", since most of it's tools derive from BSD-Versions. GNU tools are the ones that deviate from this (which I still find more convenient in day to day use).

[umanwizard]

Sure, I know there are lots of differences between GNU and macOS; that's not what I'm asking about.