Pattern Matching

Bash Reference Manual. Node: Pattern Matching

3.5.8.1: Pattern Matching

Any character that appears in a pattern, other than the special pattern characters described below, matches itself. The NUL character may not occur in a pattern. The special pattern characters must be quoted if they are to be matched literally.

The special pattern characters have the following meanings:

*

Matches any string, including the null string.

? Matches any single character.

[...]

Matches any one of the enclosed characters. A pair of characters separated by a minus sign denotes a range; any character lexically between those two characters, inclusive, is matched. If the first character following the `[' is a `!' or a `^' then any character not enclosed is matched. A `' may be matched by including it as the first or last character in the set. A `]' may be matched by including it as the first character in the set.

Within `[' and `]', character classes can be specified using the syntax [:class:], where class is one of the following classes defined in the POSIX.2 standard:

alnum   alpha   ascii   blank   cntrl   digit   graph   lower
print   punct   space   upper   xdigit

A character class matches any character belonging to that class.

Within `[' and `]', an equivalence class can be specified using the syntax [=c=], which matches all characters with the same collation weight (as defined by the current locale) as the character c.

Within `[' and `]', the syntax [.symbol.] matches the collating symbol symbol.

If the extglob shell option is enabled using the shopt builtin, several extended pattern matching operators are recognized. In the following description, a pattern-list is a list of one or more patterns separated by a `|'. Composite patterns may be formed using one or more of the following sub-patterns:

`?(pattern-list)`	Matches zero or one occurrence of the given patterns.
`*(pattern-list)`	Matches zero or more occurrences of the given patterns.
`+(pattern-list)`	Matches one or more occurrences of the given patterns.
`@(pattern-list)`	Matches exactly one of the given patterns.
`!(pattern-list)`	Matches anything except one of the given patterns.

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