18.104.22.168 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 hyphen denotes a range expression;
any character that sorts between those two characters, inclusive,
using the current locale's collating sequence and character set,
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.
The sorting order of characters in range expressions is determined by
the current locale and the value of the
LC_COLLATE shell variable,
For example, in the default C locale, '[a-dx-z]' is equivalent to
'[abcdxyz]'. Many locales sort characters in dictionary order, and in
these locales '[a-dx-z]' is typically not equivalent to '[abcdxyz]';
it might be equivalent to '[aBbCcDdxXyYz]', for example. To obtain
the traditional interpretation of ranges in bracket expressions, you can
force the use of the C locale by setting the
LC_ALL environment variable to the value 'C'.
Within '[' and ']', character classes can be specified
using the syntax
:], where class is one of the
following classes defined in the POSIX 1003.2 standard:
alnum alpha ascii blank cntrl
digit graph lower print punct
space upper word xdigit
A character class matches any character belonging to that class.
word character class matches letters, digits, and the character
Within '[' and ']', an equivalence class can be
specified using the syntax
matches all characters with the same collation weight (as defined
by the current locale) as the character c.
Within '[' and ']', the syntax
matches the collating symbol symbol.
extglob shell option is enabled using the
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
Matches zero or one occurrence of the given patterns.
Matches zero or more occurrences of the given patterns.
Matches one or more occurrences of the given patterns.
Matches exactly one of the given patterns.
Matches anything except one of the given patterns.