-p is also very commonly "password". It may take an argument, or it may cause the program to interactively prompt you for a password when you run it. Similarly,

-p is also very commonly "password". It may take an argument, or it may cause the program to interactively prompt you for a password when you run it. Similarly, -k is often "key". -a could also be "ask"; Gentoo, for example, uses it to ask you to confirm before proceeding with emerge. -h is very often "host".