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.
\ 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 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¶
- •
- 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.
- •
- 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 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 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.
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