You can type them in upper or lower case. Parameters Parameters define what the command will act upon.
Parameters are most commonly file names.
A parameter needs a space in front of it. Some sentences do not need a parameter as the VAX has built-in defaults. Some sentences need a parameter and if you don't type one in, the VAX will prompt you for one. The VAX will keep asking you for a filename until you cancel the command or type a filename in. Some sentences can have a qualifier.