What are the differences between using the terminal on a mac vs linux?

I've been using Ubuntu for the last four years. I have a basic knowledge of shell commands and I prefer working in a terminal rather than using a GUI. Recently I've started using a Mac. I've tried a few terminal commands (that I use on Ubuntu) in the Mac terminal and it seems to respond in mostly the same way. Are there any significant differences in the commands I use, the task(s) they perform or the shell environment that I should be aware of?