| fixed | denotes text that you enter literally. |
| this | means variable text, i.e. things you must fill in. |
| word | is a UNIX command, alias or shell command. |
| RET | denotes pressing a keyboard key. |
| [ ... ] | denotes an optional part. |
| US...N | letters at the right margin) describe the command category: |
| U | command is part of the operating system |
| P | public domain program |
| L | commercial licensed or registered program |
| S | command is part of the shell (command interpreter) |
| F | command can be used as filter (read from STDIN, write to STDOUT) |
| f | command can be used as an input filter |
| A | alias or function introduced to enhance UNIX command set |
| N | new command to simplify interaction with UNIX |
