File::Glob - Perl extension for BSD glob routine
- use File::Glob ':bsd_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/*>;
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. But see :bsd_glob
under EXPORTS, below.
- \ 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.
See also the POSIX FLAGS below, which can be exported individually.
:bsd_glob
The :bsd_glob
export tag exports bsd_glob() and the constants listed
below. It also overrides glob() in the calling package with one that
behaves like bsd_glob() with regard to spaces (the space is treated as part
of a file name), but supports iteration in scalar context; i.e., it
preserves the core function's feature of returning the next item each time
it is called.
:glob
The :glob
tag, now discouraged, is the old version of :bsd_glob
. It
exports the same constants and functions, but its glob() override does not
support iteration; it returns the last file name in scalar context. That
means this will loop forever:
bsd_glob
This function, which is included in the two export tags listed above,
takes one or two arguments. The first is the glob pattern. The second is
a set of flags ORed together. The available flags are listed below under
POSIX FLAGS. If the second argument is omitted, GLOB_CSH
(or
GLOB_CSH|GLOB_NOCASE
on VMS and DOSish systems) is used by default.
:nocase
and :case
These two export tags globally modify the default flags that bsd_glob()
and, except on VMS, Perl's built-in glob operator use. GLOB_NOCASE
is turned on or off, respectively.
csh_glob
The csh_glob() function can also be exported, but you should not use it directly unless you really know what you are doing. It splits the pattern into words and feeds each one to bsd_glob(). Perl's own glob() function uses this internally.
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 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.
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.
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 distribution.
glob, glob(3)
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.