There's actually a command to list all other commands that a Linux shell knows, but more than likely you're not familiar with it. If there's ever been a
Server security doesn’t need to be complicated. My security philosophy is simple: adopt principles that will protect you from the most frequent attack vectors, while keeping administration efficient enough that you won’t develop “security cruft”.... | Bryan Kennedy | Ideate, Innovate, Launch
Just a list of 20 (now 28) tools for the command line. Some are little-known, some are just too useful to miss, some are pure obscure -- I hope you find something useful that you weren't aware of yet! Use your operating system's package manager to install most of them. (Thanks for the tips, everybody!)