Here’s a good list of 10 Useful Linux Commands courtesy of TuxArena. I have used 5 of the 10 commands listed. Not bad at all. One thing I will say is, I learn something new every day with Linux. I can’t say the same for other OS, but then again I am a little biased.
Speaking of the command line, there are 687 Linux commands claimed by O’Reilley. I can’t say I know 50 of them. I don’t even know every option available from the `ls` command, or the list the contents of the directory command.
It’s one more reason I love Linux. It’s complex, powerful and stable. I wish more people use it.