File::Glob(3pm) Perl Programmers Reference Guide File::Glob(3pm)
NAME
File::Glob - Perl extension for BSD glob routine
SYNOPSIS
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/*>;
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. But see ":bsd_glob" under "EXPORTS",
below.
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.
EXPORTS
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:
use File::Glob ':glob';
while (my $file = <* copy.txt>) {
...
}
"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.
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 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.
"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.
SEE ALSO
"glob" in perlfunc, glob(3)
AUTHOR
The Perl interface was written by Nathan Torkington <gnat AT frii.com>,
and is released under the artistic license. Further modifications were
made by Greg Bacon <gbacon AT cs.edu>, Gurusamy Sarathy
<gsar AT activestate.com>, and Thomas Wegner <wegner_thomas AT 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 v5.16.3 2013-03-04 File::Glob(3pm)
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