This is really not a correct statement beyond the fact that both are a type of Unix.

What are the differences? I think of both as Unix-type sytems with macrokernels. I have no practical experience with BSDs.

Linux is not Unix: it is not derived from AT&T Unix.

	▲	ahartmetz 32 minutes ago \| parent [-]
		Linux 2.2 or 2.4 or so (possibly only Suse Linux) even had a kernel startup message "Unix compliance testing by UNIFIX" or something, back when Unix was considered more prestigious than Linux. It is / was by some official definition "a Unix", though not "UNIX the trademark by AT&T".