shell-style pattern matching
Globbing characters (wildcards) are special characters used to perform pattern
matching of pathnames and command arguments in the
shells as well as the C
library functions fnmatch(3)
. A glob pattern is a
word containing one or more unquoted ‘
’ characters, or
Globs should not be confused with the more powerful regular expressions used by
programs such as grep(1)
there is some overlap in the special characters used in regular expressions
and globs, their meaning is different.
The pattern elements have the following meaning:
- Matches any single character.
- Matches any sequence of zero or more characters.
- Matches any of the characters inside the brackets. Ranges of characters
can be specified by separating two characters by a
-’ (e.g. “[a0-9]”
matches the letter ‘a’ or any digit). In order to represent
itself, a ‘
-’ must either be quoted
or the first or last character in the character list. Similarly, a
]’ must be quoted or the first
character in the list if it is to represent itself instead of the end of
the list. Also, a ‘
!’ appearing at
the start of the list has special meaning (see below), so to represent
itself it must be quoted or appear later in the list.
Within a bracket expression, the name of a
character class enclosed in
‘[:’ and ‘:]’ stands for the list of all
characters belonging to that class. Supported character classes:
These match characters using the macros specified in
isalpha(3), and so on. A
character class may not be used as an endpoint of a range.
- Like [..], except it matches any character not inside the brackets.
- Matches the character following it verbatim. This is useful to quote the
special characters ‘
\’ such that they lose their
special meaning. For example, the pattern “\\\*\[x]\?”
matches the string “\*[x]?”.
Note that when matching a pathname, the path separator
’, is not matched by a
’, character or by a
“[..]” sequence. Thus,
would not match either.
In early versions of UNIX
, the shell did not do pattern
expansion itself. A dedicated program,
, was used to perform the
expansion and pass the results to a command. In
Version 7 AT&T UNIX
, with the introduction
of the Bourne shell, this functionality was incorporated into the shell