2.10 Special Characters

When discussing Linux with others, you should know a few names for some of the special characters that you’ll encounter. If you’re amused by this sort of thing, see the “Jargon File” (http://www.catb.org/jargon/html/) or its printed companion, The New Hacker’s Dictionary, 3rd edition, by Eric S. Raymond (MIT Press, 1996).

Table 2-1 describes a select set of the special characters, many of which you’ve already seen in this chapter. Some utilities, such as the Perl programming language, use almost all of these special characters! (Keep in mind that these are the American names for the characters.)

Table 2-1: Special Characters

Character	Name(s)	Uses
*	star, asterisk	Regular expression, glob 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	Variables, end of line
'	tick, (single) quote	Literal strings
`	backtick, backquote	Command substitution
"	double quote	Semi-literal strings
^	caret	Negation, beginning of line

p. 25

Character	Name(s)	Uses
~	tilde, squiggle	Negation, directory shortcut
#	hash, sharp, pound	Comments, preprocessor, substitutions
[ ]	(square) brackets	Ranges
{ }	braces, (curly) brackets	Statement blocks, ranges
_	underscore, under	Cheap substitute for a space used when spaces aren’t wanted or allowed, or when autocomplete algorithms get confused

note

You will often see control characters marked with a caret; for example, ^C for CTRL-C.