| Typeface | Meaning | Examples | 
|---|---|---|
| AaBbCc123 | The names of commands, files, and directories; on-screen computer output | Edit your .login file. Use ls -a to list all files. % You have mail. | 
| AaBbCc123 | What you type, when contrasted with on-screen computer output | % su Password: | 
| AaBbCc123 | Book titles, new words or terms, words to be emphasized | Read Chapter 6 in the User’s Guide. These are called class options. You must be superuser to do this. | 
| AaBbCc123 | Command-line placeholder text; replace with a real name or value | To delete a file, type rm filename. | 
Table P–2 Code Conventions
| Code Symbol | Meaning | Notation | Code Example | 
|---|---|---|---|
| [ ] | Brackets contain arguments that are optional. | O[n] | O4, O | 
| { } | Braces contain a set of choices for a required option. | d{y|n} | dy | 
| | | The “pipe” or “bar” symbol separates arguments, only one of which may be chosen. | B{dynamic|static} | Bstatic | 
| : | The colon, like the comma, is sometimes used to separate arguments. | Rdir[:dir] | R/local/libs:/U/a | 
| The ellipsis indicates omission in a series. | xinline=f1[,…fn] | xinline=alpha,dos | 
The symbol ∇ stands for a blank space where a blank is significant:
| ∇∇36.001 | 
The FORTRAN 77 standard used an older convention, spelling the name “FORTRAN” capitalized. The current convention is to use lower case: “Fortran 95”
References to online man pages appear with the topic name and section number. For example, a reference to the library routine GETENV will appear as getenv(3F), implying that the man command to access this man page would be: man -s 3F getenv.