1.10 Special Characters

If you know people who are into Linux, and you have some inexplicable desire to discuss it with them, you should know a few names for some of the special characters that you'll encounter. If you are infinitely amused by this sort of thing, look at the Jargon File (http://catb.org/~esr/jargon/html/) or its printed companion, The New Hacker's Dictionary [Raymond].

Table 1-1 on the next page lists a select set of the special characters, what they are, what people call them, and their uses. You have already seen many of these characters in this chapter. Not all meanings of each character are identified because there are too many to list. Some utilities, such as the Perl programming language, use nearly every one of these special characters! Also, keep in mind that these are the American names for the characters.

Table 1-1: Special Characters
Character	Name(s)	Uses
*	star	Regular expression, wildcard character
.	dot	Current directory, file/hostname delimiter
!	bang	Negation, command history
\|	pipe	Command pipes
/	(forward) slash	Directory delimiter, search command
\	backslash	Literals, macros (never directories)
$	dollar	Variable denotation, end of line
'	tick, (single) quote	Literal strings
`	backtick, backquote	Command substitution
"	double quote	Semi-literal strings
^	caret	Negation, beginning of line
~	tilde, squiggle	Negation, directory shortcut
#	hash, sharp, pound	Comments, preprocessor, substitutions
[]	(square) brackets	Ranges
{}	(curly) braces	Statement blocks, ranges
_	underscore	Cheap substitute for a space