File::Glob(3p) Perl Programmers Reference Guide File::Glob(3p)NAMEFile::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) rou-
tine, 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" vari-
able.
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 histor-
ical 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 con-
stant "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 avail-
able (in that order). You can inspect these values
using the standard "POSIX" extension.
"GLOB_MARK"
Each pathname that is a directory that matches the pat-
tern 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 pat-
tern. 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()).
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The FreeBSD extensions to the POSIX standard are the follow-
ing 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 spe-
cial 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.
DIAGNOSTICSbsd_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:
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"GLOB_NOSPACE"
An attempt to allocate memory failed.
"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
+ 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.
+ 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.
+ 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 dis-
tribution.
+ 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
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include "GLOB_NOCASE" in the flags.
The path separator is ':' (aka colon), not '/' (aka
slash). Mac OS users should be careful about 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 trail-
ing ':' 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
<gnat@frii.com>, and is released under the artistic license.
Further modifications were made by Greg Bacon
<gbacon@cs.uah.edu>, Gurusamy Sarathy
<gsar@activestate.com>, and Thomas Wegner
<wegner_thomas@yahoo.com>. The C glob code has the follow-
ing copyright:
Copyright (c) 1989, 1993 The Regents of the University of California.
All rights reserved.
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This code is derived from software contributed to Berkeley by
Guido van Rossum.
Redistribution and use in source and binary forms, with or without
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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