mkdir, mkdirat - create a directory


   #include <sys/stat.h>
   #include <sys/types.h>

   int mkdir(const char *pathname, mode_t mode);

   #include <fcntl.h>           /* Definition of AT_* constants */
   #include <sys/stat.h>

   int mkdirat(int dirfd, const char *pathname, mode_t mode);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       Since glibc 2.10:
           _POSIX_C_SOURCE >= 200809L
       Before glibc 2.10:


   mkdir() attempts to create a directory named pathname.

   The  argument  mode  specifies  the  mode  for  the  new directory (see
   stat(2)).  It is modified by the process's umask in the usual  way:  in
   the  absence  of  a  default  ACL, the mode of the created directory is
   (mode & ~umask & 0777).  Whether other mode bits are  honored  for  the
   created  directory  depends  on  the  operating system.  For Linux, see
   NOTES below.

   The newly created directory will be owned by the effective user  ID  of
   the process.  If the directory containing the file has the set-group-ID
   bit set, or if the filesystem  is  mounted  with  BSD  group  semantics
   (mount -o bsdgroups or, synonymously mount -o grpid), the new directory
   will inherit the group ownership from its parent; otherwise it will  be
   owned by the effective group ID of the process.

   If  the parent directory has the set-group-ID bit set, then so will the
   newly created directory.

   The mkdirat() system call operates in exactly the same way as  mkdir(),
   except for the differences described here.

   If  the  pathname given in pathname is relative, then it is interpreted
   relative to the directory referred to  by  the  file  descriptor  dirfd
   (rather  than  relative to the current working directory of the calling
   process, as is done by mkdir() for a relative pathname).

   If pathname is relative and dirfd is the special value  AT_FDCWD,  then
   pathname  is  interpreted  relative to the current working directory of
   the calling process (like mkdir()).

   If pathname is absolute, then dirfd is ignored.

   See openat(2) for an explanation of the need for mkdirat().


   mkdir() and mkdirat() return  zero  on  success,  or  -1  if  an  error
   occurred (in which case, errno is set appropriately).


   EACCES The  parent  directory  does  not  allow write permission to the
          process, or one of the directories in  pathname  did  not  allow
          search permission.  (See also path_resolution(7).)

   EDQUOT The  user's quota of disk blocks or inodes on the filesystem has
          been exhausted.

   EEXIST pathname already exists (not necessarily as a directory).   This
          includes the case where pathname is a symbolic link, dangling or

   EFAULT pathname points outside your accessible address space.

   ELOOP  Too many symbolic links were encountered in resolving pathname.

   EMLINK The number  of  links  to  the  parent  directory  would  exceed

          pathname was too long.

   ENOENT A  directory  component  in  pathname  does  not  exist  or is a
          dangling symbolic link.

   ENOMEM Insufficient kernel memory was available.

   ENOSPC The  device  containing  pathname  has  no  room  for  the   new

   ENOSPC The  new  directory  cannot  be  created because the user's disk
          quota is exhausted.

          A component used as a directory in pathname is not, in  fact,  a

   EPERM  The filesystem containing pathname does not support the creation
          of directories.

   EROFS  pathname refers to a file on a read-only filesystem.

   The following additional errors can occur for mkdirat():

   EBADF  dirfd is not a valid file descriptor.

          pathname is relative and dirfd is a file descriptor referring to
          a file other than a directory.


   mkdirat()  was  added  to  Linux  in kernel 2.6.16; library support was
   added to glibc in version 2.4.


   mkdir(): SVr4, BSD, POSIX.1-2001, POSIX.1-2008.

   mkdirat(): POSIX.1-2008.


   Under Linux, apart from the permission bits, the S_ISVTX  mode  bit  is
   also honored.

   There  are  many  infelicities in the protocol underlying NFS.  Some of
   these affect mkdir().

   Glibc notes
   On older kernels where mkdirat()  is  unavailable,  the  glibc  wrapper
   function falls back to the use of mkdir().  When pathname is a relative
   pathname, glibc constructs a pathname based on  the  symbolic  link  in
   /proc/self/fd that corresponds to the dirfd argument.


   mkdir(1),  chmod(2),  chown(2),  mknod(2), mount(2), rmdir(2), stat(2),
   umask(2), unlink(2), acl(5) path_resolution(7)


   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


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.


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.