How to Read

1. Shell

The commands in my tutorials assume a POSIX-compliant shell. So if your default shell is tcsh, then please type


before executing any commands.

2. Variables

I often use shell variables instead of dummy names in command examples so that someone can set those variables and then copy/paste the commands. (It's not great practice to do this from untrusted sources on the internet, but there's your disclaimer.) So, if my guide says to assume user=my_awesome_username, and your username is ``leethaxor'', then you should run


before running the commands after that. Those commands will substitute occurrences of ${user} with leethaxor.

I often write ${user} or even "${user}" for clarity/safety because many commands are meant to be copy/pasted. When typing it yourself, it's usually fine to just use $user if the string does not contain spaces (e.g., a username should not).