File::Glob
File::Glob(3) Perl Programmers Reference Guide File::Glob(3)
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 proto-
type--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.
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 sep-
arately 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" (usu-
ally found in limits.h). If your system does not define this con-
stant, 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 following flags:
"GLOB_BRACE"
Pre-process the string to expand "{pat,pat,...}" strings like
csh(1). The pattern ’{}’ is left unexpanded for historical rea-
sons (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 charac-
ter. (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.
"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 char-
acter. 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, back-
slashes (under GLOB_QUOTE) only quote the glob metacharacters ’[’,
’]’, ’{’, ’}’, ’-’, ’~’, and backslash itself. All other back-
slashes 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 distribution.
· 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 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 rela-
tive pathname on Mac OS must always begin with a ’:’, except when
specifying a file or directory name in the current working direc-
tory, 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 rela-
tive 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 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
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.
perl v5.8.8 2001-09-21 File::Glob(3)
