dirname(3)
NAME
basename, dirname - parse pathname components
SYNOPSIS
#include <libgen.h> char *dirname(char *path); char *basename(char *path);
DESCRIPTION
Warning: there are two different functions basename() - see below.
The functions dirname() and basename() break a null-terminated pathname
string into directory and filename components. In the usual case,
dirname() returns the string up to, but not including, the final '/',
and basename() returns the component following the final '/'. Trailing
'/' characters are not counted as part of the pathname.
If path does not contain a slash, dirname() returns the string "."
while basename() returns a copy of path. If path is the string "/",
then both dirname() and basename() return the string "/". If path is a
null pointer or points to an empty string, then both dirname() and
basename() return the string ".".
Concatenating the string returned by dirname(), a "/", and the string
returned by basename() yields a complete pathname.
Both dirname() and basename() may modify the contents of path, so it
may be desirable to pass a copy when calling one of these functions.
These functions may return pointers to statically allocated memory
which may be overwritten by subsequent calls. Alternatively, they may
return a pointer to some part of path, so that the string referred to
by path should not be modified or freed until the pointer returned by
the function is no longer required.
The following list of examples (taken from SUSv2) shows the strings
returned by dirname() and basename() for different paths:
path dirname basename
/usr/lib /usr lib
/usr/ / usr
usr . usr
/ / /
. . .
.. . ..
RETURN VALUE
Both dirname() and basename() return pointers to null-terminated strings. (Do not pass these pointers to free(3).)
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7). ┌──────────────────────┬───────────────┬─────────┐ │Interface │ Attribute │ Value │ ├──────────────────────┼───────────────┼─────────┤ │basename(), dirname() │ Thread safety │ MT-Safe │ └──────────────────────┴───────────────┴─────────┘
CONFORMING TO
POSIX.1-2001, POSIX.1-2008.
NOTES
There are two different versions of basename() - the POSIX version
described above, and the GNU version, which one gets after
#define _GNU_SOURCE /* See feature_test_macros(7) */
#include <string.h>
The GNU version never modifies its argument, and returns the empty
string when path has a trailing slash, and in particular also when it
is "/". There is no GNU version of dirname().
With glibc, one gets the POSIX version of basename() when <libgen.h> is
included, and the GNU version otherwise.
BUGS
In the glibc implementation, the POSIX versions of these functions modify the path argument, and segfault when called with a static string such as "/usr/". Before glibc 2.2.1, the glibc version of dirname() did not correctly handle pathnames with trailing '/' characters, and generated a segfault if given a NULL argument.
EXAMPLE
char *dirc, *basec, *bname, *dname;
char *path = "/etc/passwd";
dirc = strdup(path);
basec = strdup(path);
dname = dirname(dirc);
bname = basename(basec);
printf("dirname=%s, basename=%s\n", dname, bname);
SEE ALSO
basename(1), dirname(1)
COLOPHON
This page is part of release 4.09 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/.
Opportunity
Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.
Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.
Free Software
Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.
Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.
Free Books
The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.
Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.
Education
Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.
Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.
