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man : File::Glob(3p)
File::Glob(3p) Perl Programmers Reference Guide File::Glob(3p)
NAME
File::Glob - Perl extension for BSD glob routine
SYNOPSIS
use File::Glob ':glob';
@list = bsd_glob('*.[ch]');
$homedir = bsd_glob('~gnat', GLOB_TILDE | GLOB_ERR);
if (GLOB_ERROR) {
# an error occurred reading $homedir
}
## override the core glob (CORE::glob() does this automatically
## by default anyway, since v5.6.0)
use File::Glob ':globally';
my @sources = <*.{c,h,y}>;
## override the core glob, forcing case sensitivity
use File::Glob qw(:globally :case);
my @sources = <*.{c,h,y}>;
## override the core glob forcing case insensitivity
use File::Glob qw(:globally :nocase);
my @sources = <*.{c,h,y}>;
## glob on all files in home directory
use File::Glob ':globally';
my @sources = <~gnat/*>;
DESCRIPTION
The glob angle-bracket operator "<>" is a pathname
generator that implements the rules for file name pattern
matching used by Unix-like shells such as the Bourne shell
or C shell.
File::Glob::bsd_glob() implements the FreeBSD glob(3)
routine, which is a superset of the POSIX glob()
(described in IEEE Std 1003.2 "POSIX.2"). bsd_glob()
takes a mandatory "pattern" argument, and an optional
"flags" argument, and returns a list of filenames matching
the pattern, with interpretation of the pattern modified
by the "flags" variable.
Since v5.6.0, Perl's CORE::glob() is implemented in terms
of bsd_glob(). Note that they don't share the same
prototype--CORE::glob() only accepts a single argument.
Due to historical reasons, CORE::glob() will also split
its argument on whitespace, treating it as multiple
patterns, whereas bsd_glob() considers them as one
pattern.
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META CHARACTERS
\ Quote the next metacharacter
[] Character class
{} Multiple pattern
* Match any string of characters
? Match any single character
~ User name home directory
The metanotation "a{b,c,d}e" is a shorthand for "abe ace
ade". Left to right order is preserved, with results of
matches being sorted separately at a low level to preserve
this order. As a special case "{", "}", and "{}" are
passed undisturbed.
POSIX FLAGS
The POSIX defined flags for bsd_glob() are:
"GLOB_ERR"
Force bsd_glob() to return an error when it encounters
a directory it cannot open or read. Ordinarily
bsd_glob() continues to find matches.
"GLOB_LIMIT"
Make bsd_glob() return an error (GLOB_NOSPACE) when
the pattern expands to a size bigger than the system
constant "ARG_MAX" (usually found in limits.h). If
your system does not define this constant, bsd_glob()
uses "sysconf(_SC_ARG_MAX)" or "_POSIX_ARG_MAX" where
available (in that order). You can inspect these
values using the standard "POSIX" extension.
"GLOB_MARK"
Each pathname that is a directory that matches the
pattern has a slash appended.
"GLOB_NOCASE"
By default, file names are assumed to be case
sensitive; this flag makes bsd_glob() treat case
differences as not significant.
"GLOB_NOCHECK"
If the pattern does not match any pathname, then
bsd_glob() returns a list consisting of only the
pattern. If "GLOB_QUOTE" is set, its effect is
present in the pattern returned.
"GLOB_NOSORT"
By default, the pathnames are sorted in ascending
ASCII order; this flag prevents that sorting (speeding
up bsd_glob()).
The FreeBSD extensions to the POSIX standard are the
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following flags:
"GLOB_BRACE"
Pre-process the string to expand "{pat,pat,...}"
strings like csh(1). The pattern '{}' is left
unexpanded for historical reasons (and csh(1) does the
same thing to ease typing of find(1) patterns).
"GLOB_NOMAGIC"
Same as "GLOB_NOCHECK" but it only returns the pattern
if it does not contain any of the special characters
"*", "?" or "[". "NOMAGIC" is provided to simplify
implementing the historic csh(1) globbing behaviour
and should probably not be used anywhere else.
"GLOB_QUOTE"
Use the backslash ('\') character for quoting: every
occurrence of a backslash followed by a character in
the pattern is replaced by that character, avoiding
any special interpretation of the character. (But see
below for exceptions on DOSISH systems).
"GLOB_TILDE"
Expand patterns that start with '~' to user name home
directories.
"GLOB_CSH"
For convenience, "GLOB_CSH" is a synonym for
"GLOB_BRACE | GLOB_NOMAGIC | GLOB_QUOTE | GLOB_TILDE |
GLOB_ALPHASORT".
The POSIX provided "GLOB_APPEND", "GLOB_DOOFFS", and the
FreeBSD extensions "GLOB_ALTDIRFUNC", and "GLOB_MAGCHAR"
flags have not been implemented in the Perl version
because they involve more complex interaction with the
underlying C structures.
The following flag has been added in the Perl
implementation for csh compatibility:
"GLOB_ALPHASORT"
If "GLOB_NOSORT" is not in effect, sort filenames is
alphabetical order (case does not matter) rather than
in ASCII order.
DIAGNOSTICS
bsd_glob() returns a list of matching paths, possibly zero
length. If an error occurred, &File::Glob::GLOB_ERROR
will be non-zero and $! will be set.
&File::Glob::GLOB_ERROR is guaranteed to be zero if no
error occurred, or one of the following values otherwise:
"GLOB_NOSPACE"
An attempt to allocate memory failed.
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"GLOB_ABEND"
The glob was stopped because an error was encountered.
In the case where bsd_glob() has found some matching
paths, but is interrupted by an error, it will return a
list of filenames and set &File::Glob::ERROR.
Note that bsd_glob() deviates from POSIX and FreeBSD
glob(3) behaviour by not considering "ENOENT" and
"ENOTDIR" as errors - bsd_glob() will continue processing
despite those errors, unless the "GLOB_ERR" flag is set.
Be aware that all filenames returned from File::Glob are
tainted.
NOTES
o If you want to use multiple patterns, e.g.
"bsd_glob("a* b*")", you should probably throw them in
a set as in "bsd_glob("{a*,b*}")". This is because
the argument to bsd_glob() isn't subjected to parsing
by the C shell. Remember that you can use a backslash
to escape things.
o On DOSISH systems, backslash is a valid directory
separator character. In this case, use of backslash
as a quoting character (via GLOB_QUOTE) interferes
with the use of backslash as a directory separator.
The best (simplest, most portable) solution is to use
forward slashes for directory separators, and
backslashes for quoting. However, this does not match
"normal practice" on these systems. As a concession to
user expectation, therefore, backslashes (under
GLOB_QUOTE) only quote the glob metacharacters '[',
']', '{', '}', '-', '~', and backslash itself. All
other backslashes are passed through unchanged.
o Win32 users should use the real slash. If you really
want to use backslashes, consider using Sarathy's
File::DosGlob, which comes with the standard Perl
distribution.
o Mac OS (Classic) users should note a few differences.
Since Mac OS is not Unix, when the glob code
encounters a tilde glob (e.g. ~user) and the
"GLOB_TILDE" flag is used, it simply returns that
pattern without doing any expansion.
Glob on Mac OS is case-insensitive by default (if you
don't use any flags). If you specify any flags at all
and still want glob to be case-insensitive, you must
include "GLOB_NOCASE" in the flags.
The path separator is ':' (aka colon), not '/' (aka
slash). Mac OS users should be careful about
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specifying relative pathnames. While a full path
always begins with a volume name, a relative pathname
should always begin with a ':'. If specifying a
volume name only, a trailing ':' is required.
The specification of pathnames in glob patterns
adheres to the usual Mac OS conventions: The path
separator is a colon ':', not a slash '/'. A full path
always begins with a volume name. A relative pathname
on Mac OS must always begin with a ':', except when
specifying a file or directory name in the current
working directory, where the leading colon is
optional. If specifying a volume name only, a trailing
':' is required. Due to these rules, a glob like <*:>
will find all mounted volumes, while a glob like <*>
or <:*> will find all files and directories in the
current directory.
Note that updirs in the glob pattern are resolved
before the matching begins, i.e. a pattern like
"*HD:t?p::a*" will be matched as "*HD:a*". Note also,
that a single trailing ':' in the pattern is ignored
(unless it's a volume name pattern like "*HD:"), i.e.
a glob like <:*:> will find both directories and files
(and not, as one might expect, only directories). You
can, however, use the "GLOB_MARK" flag to distinguish
(without a file test) directory names from file names.
If the "GLOB_MARK" flag is set, all directory paths
will have a ':' appended. Since a directory like
'lib:' is not a valid relative path on Mac OS, both a
leading and a trailing colon will be added, when the
directory name in question doesn't contain any colons
(e.g. 'lib' becomes ':lib:').
SEE ALSO
"glob" in perlfunc, glob(3)
AUTHOR
The Perl interface was written by Nathan Torkington
<gnatATfrii.com>, and is released under the artistic
license. Further modifications were made by Greg Bacon
<gbaconATcs.edu>, Gurusamy Sarathy
<gsarATactivestate.com>, and Thomas Wegner
<wegner_thomasATyahoo.com>. The C glob code has the
following copyright:
Copyright (c) 1989, 1993 The Regents of the University of California.
All rights reserved.
This code is derived from software contributed to Berkeley by
Guido van Rossum.
Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
3. Neither the name of the University nor the names of its contributors
may be used to endorse or promote products derived from this software
without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.
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