Hdi2u S02

Anatomy of a Command

<command> <options/parameters> <arguments>

• <command> what do I want to do?
• <options/parameters> how do I want to do it?
• <arguments>, on what do I want to do it?

• first word you supply on the command line is interpreted by the system as a command, an operation.
• Items that appear after that on on the same line are separated by spaces.
• Most commands have options available that will alter the way the command functions.
• after the options we have what are called arguments, often these are input files.
• With some commands you don't need to issue any parameters or arguments. This is because you are using the default settings.
• To know the default settings the documentation must be read.

• If a command runs successfully, it often will not report anything back to you
• You can of course tell by the nature of the putput files it produced.
• If a command is unsuccessful, it will report an error. Most of the time, these are informative, even if a bit cryptic.
• However, if you forgot to specify the input file, you should be able to interpret that.