Linux in a Nutshell, 6th Edition

Filename Metacharacters

Characters	Meaning
*	Match any string of zero or more characters.
?	Match any single character.
[ abc...]	Match any one of the enclosed characters; a hyphen can specify a range (e.g., a–z, A–Z, 0–9).
[! abc...], [^ abc...]	Match any character not enclosed as above.
~	Home directory of the current user.
~ name	Home directory of user name.
~+	Current working directory ($PWD).
~-	Previous working directory ($OLDPWD).

With the extglob option on:

Characters	Meaning
?( pattern)	Match zero or one instance of pattern.
*( pattern)	Match zero or more instances of pattern.
+( pattern)	Match one or more instances of pattern.
@( pattern)	Match exactly one instance of pattern.
!( pattern)	Match any strings that don’t match pattern.

This pattern can be a sequence of patterns separated by |, meaning that the match applies to any of the patterns. This extended syntax resembles that available in egrep and awk.

Bash supports the POSIX [[= c =]] notation for matching characters that have the same weight, and [[. c .]] for specifying collating sequences. In addition, character classes, of the form [[: class :]], allow you to match the following classes of characters.

Class	Characters matched	Class	Characters matched
alnum	Alphanumeric characters	graph	Nonspace characters
alpha	Alphabetic characters	print	Printable characters
blank	Space or tab	punct	Punctuation characters
cntrl	Control characters	space	Whitespace characters
digit	Decimal digits	upper	Uppercase characters
lower	Lowercase characters	xdigit	Hexadecimal digits

Bash also accepts ...