复制内容到剪贴板
代码:
Pathname Expansion
After word splitting, unless the -f option has been set, bash scans
each word for the characters *, ?, and [. If one of these characters
appears, then the word is regarded as a pattern, and replaced with an
alphabetically sorted list of file names matching the pattern. If no
matching file names are found, and the shell option nullglob is dis-
abled, the word is left unchanged. If the nullglob option is set, and
no matches are found, the word is removed. If the shell option nocase-
glob is enabled, the match is performed without regard to the case of
alphabetic characters. When a pattern is used for pathname expansion,
the character ‘‘.’’ at the start of a name or immediately following a
slash must be matched explicitly, unless the shell option dotglob is
set. When matching a pathname, the slash character must always be
matched explicitly. In other cases, the ‘‘.’’ character is not
treated specially. See the description of shopt below under SHELL
BUILTIN COMMANDS for a description of the nocaseglob, nullglob, and
dotglob shell options.
The GLOBIGNORE shell variable may be used to restrict the set of file
names matching a pattern. If GLOBIGNORE is set, each matching file
name that also matches one of the patterns in GLOBIGNORE is removed
from the list of matches. The file names ‘‘.’’ and ‘‘..’’ are always
ignored, even when GLOBIGNORE is set. However, setting GLOBIGNORE has
the effect of enabling the dotglob shell option, so all other file
names beginning with a ‘‘.’’ will match. To get the old behavior of
ignoring file names beginning with a ‘‘.’’, make ‘‘.*’’ one of the
patterns in GLOBIGNORE. The dotglob option is disabled when GLOBIGNORE
is unset.
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 charac-
ters separated by a hyphen denotes a range expression; any char-
acter 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. The sorting order
of characters in range expressions is determined by the current
locale and the value of the LC_COLLATE shell variable, if set.
A - may be matched by including it as the first or last charac-
ter 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 word xdigit
A character class matches any character belonging to that class.
The word character class matches letters, digits, and the char-
acter _.
Within [ and ], an equivalence class can be specified using the
syntax [=c=], which matches all characters with the same colla-
tion weight (as defined by the current locale) as the character
c.
Within [ and ], the syntax [.symbol.] matches the collating sym-
bol 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 fol-
lowing 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
