The highlighting commands can be used to extract useful information from the file, such as lists of functions or file names. It is possible, for example, to write a program in Emacs Lisp (or a keyboard macro) to insert an index entry after every paragraph that contains words or phrases marked by a specified command. You could do this to construct an index of functions if you had not already made the entries.

The commands serve a variety of purposes:

@code{sample-code}

Indicate text that is a literal example of a piece of a program.

@kbd{keyboard-characters}

Indicate keyboard input.

@key{key-name}

Indicate the conventional name for a key on a keyboard.

@samp{text}

Indicate text that is a literal example of a sequence of characters.

@var{metasyntactic-variable}

Indicate a metasyntactic variable.

@env{environment-variable}

Indicate an environment variable.

@file{file-name}

Indicate the name of a file.

@command{command-name}

Indicate the name of a command.

@option{option}

Indicate a command-line option.

@dfn{term}

Indicate the introductory or defining use of a term.

@cite{reference}

Indicate the name of a book.

@acronym{acronym}

Indicate an acronym.

@url{uniform-resource-locator}

Indicate a uniform resource locator for the World Wide Web.

@email{email-address[, displayed-text]}

Indicate an electronic mail address.