Mac OS X is based on BSD. BSD is similar to Linux but it is not Linux. However a big number of commands is identical. That means that while many aspects will be similar to linux, not EVERYTHING is the same.

Is Mac a Unix or Linux?

macOS is a UNIX 03-compliant operating system certified by The Open Group.

Is the Mac terminal Linux?

Mac OS X is a Unix OS and its command line is 99.9% the same as any Linux distribution. bash is your default shell and you can compile all of the same programs and utilities. There’s no notable difference.