Section (3) glob
Name
glob, globfree — find pathnames matching a pattern, free memory from glob()
Synopsis
#include <glob.h>
int
glob( |
const char *pattern, |
int flags, | |
int (*errfunc)( const char
*epath, int eerrno) , |
|
glob_t *pglob) ; |
void
globfree( |
glob_t *pglob) ; |
DESCRIPTION
The glob
() function searches
for all the pathnames matching pattern
according to the rules
used by the shell (see glob(7)). No tilde
expansion or parameter substitution is done; if you want
these, use wordexp(3).
The globfree
() function
frees the dynamically allocated storage from an earlier call
to glob
().
The results of a glob
() call
are stored in the structure pointed to by pglob
. This structure is of
type glob_t (declared in
<
glob.h
>
and
includes the following elements defined by POSIX.2 (more may
be present as an extension):
typedef | struct { | |||
size_t | gl_pathc ; |
/* Count of paths matched so far */
|
||
char | ** | gl_pathv ; |
/* List of matched pathnames. */
|
|
size_t | gl_offs ; |
/* Slots to reserve in gl_pathv. */
|
||
} glob_t; |
Results are stored in dynamically allocated storage.
The argument flags
is made up of the bitwise OR of zero or more the following
symbolic constants, which modify the behavior of glob
():
GLOB_ERR
-
Return upon a read error (because a directory does not have read permission, for example). By default,
glob
() attempts carry on despite errors, reading all of the directories that it can. GLOB_MARK
-
Append a slash to each path which corresponds to a directory.
GLOB_NOSORT
-
Don_zsingle_quotesz_t sort the returned pathnames. The only reason to do this is to save processing time. By default, the returned pathnames are sorted.
GLOB_DOOFFS
-
Reserve
pglob−>gl_offs
slots at the beginning of the list of strings inpglob−>pathv
. The reserved slots contain null pointers. GLOB_NOCHECK
-
If no pattern matches, return the original pattern. By default,
glob
() returnsGLOB_NOMATCH
if there are no matches. GLOB_APPEND
-
Append the results of this call to the vector of results returned by a previous call to
glob
(). Do not set this flag on the first invocation ofglob
(). GLOB_NOESCAPE
-
Don_zsingle_quotesz_t allow backslash (_zsingle_quotesz_\_zsingle_quotesz_) to be used as an escape character. Normally, a backslash can be used to quote the following character, providing a mechanism to turn off the special meaning metacharacters.
flags
may also
include any of the following, which are GNU extensions and
not defined by POSIX.2:
GLOB_PERIOD
-
Allow a leading period to be matched by metacharacters. By default, metacharacters can_zsingle_quotesz_t match a leading period.
GLOB_ALTDIRFUNC
-
Use alternative functions
pglob−>gl_closedir
,pglob−>gl_readdir
,pglob−>gl_opendir
,pglob−>gl_lstat
, andpglob−>gl_stat
for filesystem access instead of the normal library functions. GLOB_BRACE
-
Expand csh(1) style brace expressions of the form
{a,b}
. Brace expressions can be nested. Thus, for example, specifying the pattern {foo/{,cat,dog},bar} would return the same results as four separateglob
() calls using the strings: foo/, foo/cat, foo/dog, and bar. GLOB_NOMAGIC
-
If the pattern contains no metacharacters, then it should be returned as the sole matching word, even if there is no file with that name.
GLOB_TILDE
-
Carry out tilde expansion. If a tilde (_zsingle_quotesz_~_zsingle_quotesz_) is the only character in the pattern, or an initial tilde is followed immediately by a slash (_zsingle_quotesz_/_zsingle_quotesz_), then the home directory of the caller is substituted for the tilde. If an initial tilde is followed by a username (e.g., ~andrea/bin), then the tilde and username are substituted by the home directory of that user. If the username is invalid, or the home directory cannot be determined, then no substitution is performed.
GLOB_TILDE_CHECK
-
This provides behavior similar to that of
GLOB_TILDE
. The difference is that if the username is invalid, or the home directory cannot be determined, then instead of using the pattern itself as the name,glob
() returnsGLOB_NOMATCH
to indicate an error. GLOB_ONLYDIR
-
This is a hint to
glob
() that the caller is interested only in directories that match the pattern. If the implementation can easily determine file-type information, then nondirectory files are not returned to the caller. However, the caller must still check that returned files are directories. (The purpose of this flag is merely to optimize performance when the caller is interested only in directories.)
If errfunc
is not
NULL, it will be called in case of an error with the
arguments epath
, a
pointer to the path which failed, and eerrno
, the value of errno
as returned from one of the calls to
opendir(3), readdir(3), or stat(2). If errfunc
returns nonzero, or if
GLOB_ERR
is set, glob
() will terminate after the call to
errfunc
.
Upon successful return, pglob−>gl_pathc
contains the number of matched pathnames and pglob−>gl_pathv
contains a pointer to the list of pointers to matched
pathnames. The list of pointers is terminated by a null
pointer.
It is possible to call glob
() several times. In that case, the
GLOB_APPEND
flag has to be set
in flags
on the
second and later invocations.
As a GNU extension, pglob−>gl_flags
is
set to the flags specified, ored with GLOB_MAGCHAR
if any metacharacters were
found.
RETURN VALUE
On successful completion, glob
() returns zero. Other possible returns
are:
GLOB_NOSPACE
-
for running out of memory,
GLOB_ABORTED
-
for a read error, and
GLOB_NOMATCH
-
for no found matches.
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).
Interface | Attribute | Value |
glob () |
Thread safety |
MT-Unsafe race:utent env sig:ALRM timer locale |
globfree () |
Thread safety | MT-Safe |
In the above table, utent
in
race:utent
signifies that if any of the functions setutent(3), getutent(3), or endutent(3) are used in
parallel in different threads of a program, then data races
could occur. glob
() calls those
functions, so we use race:utent to remind users.
NOTES
The structure elements gl_pathc
and gl_offs
are declared as
size_t in glibc 2.1, as they should
be according to POSIX.2, but are declared as int in glibc 2.0.
BUGS
The glob
() function may fail
due to failure of underlying function calls, such as
malloc(3) or opendir(3). These will
store their error code in errno
.
EXAMPLE
One example of use is the following code, which simulates typing
ls −l *.c ../*.c
in the shell:
glob_t globbuf; globbuf.gl_offs = 2; glob(*.c, GLOB_DOOFFS, NULL, &globbuf); glob(../*.c, GLOB_DOOFFS | GLOB_APPEND, NULL, &globbuf); globbuf.gl_pathv[0] = ls; globbuf.gl_pathv[1] = −l; execvp(ls, &globbuf.gl_pathv[0]);
SEE ALSO
ls(1), sh(1), stat(2), exec(3), fnmatch(3), malloc(3), opendir(3), readdir(3), wordexp(3), glob(7)
COLOPHON
This page is part of release 5.04 of the Linux man-pages
project. A
description of the project, information about reporting bugs,
and the latest version of this page, can be found at
https://www.kernel.org/doc/man−pages/.
Copyright (c) 1993 by Thomas Koenig (ig25rz.uni-karlsruhe.de) %%%LICENSE_START(VERBATIM) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. %%%LICENSE_END Modified Wed Jul 28 11:12:17 1993 by Rik Faith (faithcs.unc.edu) Modified Mon May 13 23:08:50 1996 by Martin Schulze (joeylinux.de) Modified 11 May 1998 by Joseph S. Myers (jsm28cam.ac.uk) Modified 990912 by aeb 2007-10-10 mtk Added description of GLOB_TILDE_NOMATCH Expanded the description of various flags Various wording fixes. |
Section (7) glob
Name
glob — globbing pathnames
DESCRIPTION
Long ago, in UNIX V6, there was a program /etc/glob
that would expand wildcard
patterns. Soon afterward this became a shell built-in.
These days there is also a library routine glob(3) that will perform this function for a user program.
The rules are as follows (POSIX.2, 3.13).
Wildcard matching
A string is a wildcard pattern if it contains one of the characters _zsingle_quotesz_?_zsingle_quotesz_, _zsingle_quotesz_*_zsingle_quotesz_ or _zsingle_quotesz_[_zsingle_quotesz_. Globbing is the operation that expands a wildcard pattern into the list of pathnames matching the pattern. Matching is defined by:
A _zsingle_quotesz_?_zsingle_quotesz_ (not between brackets) matches any single character.
A _zsingle_quotesz_*_zsingle_quotesz_ (not between brackets) matches any string, including the empty string.
Character classes
An expression [...]
where the first
character after the leading _zsingle_quotesz_[_zsingle_quotesz_ is not an _zsingle_quotesz_!_zsingle_quotesz_ matches a
single character, namely any of the characters enclosed by
the brackets. The string enclosed by the brackets cannot be
empty; therefore _zsingle_quotesz_]_zsingle_quotesz_ can be allowed between the brackets,
provided that it is the first character. (Thus, [][!]
matches the three
characters _zsingle_quotesz_[_zsingle_quotesz_, _zsingle_quotesz_]_zsingle_quotesz_ and _zsingle_quotesz_!_zsingle_quotesz_.)
Ranges
There is one special convention: two characters
separated by _zsingle_quotesz_−_zsingle_quotesz_ denote a range. (Thus, [A−Fa−f0−9]
is equivalent to [ABCDEFabcdef0123456789]
.)
One may include _zsingle_quotesz_−_zsingle_quotesz_ in its literal meaning by making
it the first or last character between the brackets. (Thus,
[]−]
matches just the two characters _zsingle_quotesz_]_zsingle_quotesz_ and _zsingle_quotesz_−_zsingle_quotesz_, and
[−−0]
matches
the three characters _zsingle_quotesz_−_zsingle_quotesz_, _zsingle_quotesz_._zsingle_quotesz_, _zsingle_quotesz_0_zsingle_quotesz_, since _zsingle_quotesz_/_zsingle_quotesz_ cannot
be matched.)
Complementation
An expression [!...]
matches a single
character, namely any character that is not matched by the
expression obtained by removing the first _zsingle_quotesz_!_zsingle_quotesz_ from it.
(Thus, [!]a−]
matches any
single character except _zsingle_quotesz_]_zsingle_quotesz_, _zsingle_quotesz_a_zsingle_quotesz_ and _zsingle_quotesz_−_zsingle_quotesz_.)
One can remove the special meaning of _zsingle_quotesz_?_zsingle_quotesz_, _zsingle_quotesz_*_zsingle_quotesz_ and _zsingle_quotesz_[_zsingle_quotesz_
by preceding them by a backslash, or, in case this is part
of a shell command line, enclosing them in quotes. Between
brackets these characters stand for themselves. Thus,
[[?*]
matches
the four characters _zsingle_quotesz_[_zsingle_quotesz_, _zsingle_quotesz_?_zsingle_quotesz_, _zsingle_quotesz_*_zsingle_quotesz_ and _zsingle_quotesz_\_zsingle_quotesz_.
Pathnames
Globbing is applied on each of the components of a
pathname separately. A _zsingle_quotesz_/_zsingle_quotesz_ in a pathname cannot be matched
by a _zsingle_quotesz_?_zsingle_quotesz_ or _zsingle_quotesz_*_zsingle_quotesz_ wildcard, or by a range like [.−0]
. A range
containing an explicit _zsingle_quotesz_/_zsingle_quotesz_ character is syntactically
incorrect. (POSIX requires that syntactically incorrect
patterns are left unchanged.)
If a filename starts with a _zsingle_quotesz_._zsingle_quotesz_, this character must be matched explicitly. (Thus, rm * will not remove .profile, and tar c * will not archive all your files; tar c . is better.)
Empty lists
The nice and simple rule given above: expand a wildcard pattern into the list of matching pathnames was the original UNIX definition. It allowed one to have patterns that expand into an empty list, as in
xv −wait 0 *.gif *.jpg
where perhaps no *.gif files are present (and this is
not an error). However, POSIX requires that a wildcard
pattern is left unchanged when it is syntactically
incorrect, or the list of matching pathnames is empty. With
bash
one can
force the classical behavior using this command:
shopt −s nullglob
(Similar problems occur elsewhere. For example, where old scripts have
rm `find . −name *~`
new scripts require
rm −f nosuchfile `find . −name *~`
to avoid error messages from rm called with an empty argument list.)
NOTES
Regular expressions
Note that wildcard patterns are not regular expressions, although they are a bit similar. First of all, they match filenames, rather than text, and secondly, the conventions are not the same: for example, in a regular expression _zsingle_quotesz_*_zsingle_quotesz_ means zero or more copies of the preceding thing.
Now that regular expressions have bracket expressions
where the negation is indicated by a _zsingle_quotesz_^_zsingle_quotesz_, POSIX has
declared the effect of a wildcard pattern [^...]
to be
undefined.
Character classes and internationalization
Of course ranges were originally meant to be ASCII
ranges, so that [
−%] stands for [ !#$%] and [a−z]
stands for
any lowercase letter. Some UNIX implementations
generalized this so that a range X−Y stands for the
set of characters with code between the codes for X and for
Y. However, this requires the user to know the character
coding in use on the local system, and moreover, is not
convenient if the collating sequence for the local alphabet
differs from the ordering of the character codes.
Therefore, POSIX extended the bracket notation greatly,
both for wildcard patterns and for regular expressions. In
the above we saw three types of items that can occur in a
bracket expression: namely (i) the negation, (ii) explicit
single characters, and (iii) ranges. POSIX specifies ranges
in an internationally more useful way and adds three more
types:
(iii) Ranges X−Y comprise all characters that fall
between X and Y (inclusive) in the current collating
sequence as defined by the LC_COLLATE
category in the current
locale.
(iv) Named character classes, like
[:alnum:] [:alpha:] [:blank:] [:cntrl:] [:digit:] [:graph:] [:lower:] [:print:] [:punct:] [:space:] [:upper:] [:xdigit:]
so that one can say [[:lower:]]
instead of
[a−z]
,
and have things work in Denmark, too, where there are three
letters past _zsingle_quotesz_z_zsingle_quotesz_ in the alphabet. These character classes
are defined by the LC_CTYPE
category in the current locale.
(v) Collating symbols, like [.ch.]
or [.a-acute.]
, where the
string between [.
and .]
is a collating element
defined for the current locale. Note that this may be a
multicharacter element.
(vi) Equivalence class expressions, like [=a=]
, where the string
between [=
and
=]
is any
collating element from its equivalence class, as defined
for the current locale. For example, [[=a=]]
might be
equivalent to [aáàäâ]
,
that is, to [a[.a-acute.][.a-grave.][.a-umlaut.][.a-circumflex.]]
.
COLOPHON
This page is part of release 4.16 of the Linux man-pages
project. A
description of the project, information about reporting bugs,
and the latest version of this page, can be found at
https://www.kernel.org/doc/man−pages/.
Copyright (c) 1998 Andries Brouwer %%%LICENSE_START(GPLv2+_DOC_FULL) This is free documentation; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. The GNU General Public License_zsingle_quotesz_s references to object code and executables are to be interpreted as the output of any document formatting or typesetting system, including intermediate and printed output. This manual is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this manual; if not, see <http://www.gnu.org/licenses/>. %%%LICENSE_END 2003-08-24 fix for / by John Kristoff + joey |