MKDIR(1P) POSIX Programmer's Manual MKDIR(1P)

This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

mkdir — make directories

mkdir [-p] [-m mode] dir...

The mkdir utility shall create the directories specified by the operands, in the order specified.

For each dir operand, the mkdir utility shall perform actions equivalent to the mkdir() function defined in the System Interfaces volume of POSIX.1‐2017, called with the following arguments:

The dir operand is used as the path argument.
The value of the bitwise-inclusive OR of S_IRWXU, S_IRWXG, and S_IRWXO is used as the mode argument. (If the -m option is specified, the value of the mkdir() mode argument is unspecified, but the directory shall at no time have permissions less restrictive than the -m mode option-argument.)

The mkdir utility shall conform to the Base Definitions volume of POSIX.1‐2017, Section 12.2, Utility Syntax Guidelines.

The following options shall be supported:

Set the file permission bits of the newly-created directory to the specified mode value. The mode option-argument shall be the same as the mode operand defined for the chmod utility. In the symbolic_mode strings, the op characters '+' and '-' shall be interpreted relative to an assumed initial mode of a=rwx; '+' shall add permissions to the default mode, '-' shall delete permissions from the default mode.
Create any missing intermediate pathname components.

For each dir operand that does not name an existing directory, before performing the actions described in the DESCRIPTION above, the mkdir utility shall create any pathname components of the path prefix of dir that do not name an existing directory by performing actions equivalent to first calling the mkdir() function with the following arguments:

A pathname naming the missing pathname component, ending with a trailing <slash> character, as the path argument
The value zero as the mode argument

and then calling the chmod() function with the following arguments:

The same path argument as in the mkdir() call
The value (S_IWUSR|S_IXUSR|~filemask)&0777 as the mode argument, where filemask is the file mode creation mask of the process (see the System Interfaces volume of POSIX.1‐2017, umask())

Each dir operand that names an existing directory shall be ignored without error.

The following operand shall be supported:

A pathname of a directory to be created.

Not used.


The following environment variables shall affect the execution of mkdir:

Provide a default value for the internationalization variables that are unset or null. (See the Base Definitions volume of POSIX.1‐2017, Section 8.2, Internationalization Variables for the precedence of internationalization variables used to determine the values of locale categories.)
If set to a non-empty string value, override the values of all the other internationalization variables.
Determine the locale for the interpretation of sequences of bytes of text data as characters (for example, single-byte as opposed to multi-byte characters in arguments).

Determine the locale that should be used to affect the format and contents of diagnostic messages written to standard error.
Determine the location of message catalogs for the processing of LC_MESSAGES.


Not used.

The standard error shall be used only for diagnostic messages.



The following exit values shall be returned:

All the specified directories were created successfully, or the -p option was specified and all the specified directories either already existed or were created successfully.
An error occurred.


The following sections are informative.

The default file mode for directories is a=rwx (777 on most systems) with selected permissions removed in accordance with the file mode creation mask. For intermediate pathname components created by mkdir, the mode is the default modified by u+wx so that the subdirectories can always be created regardless of the file mode creation mask; if different ultimate permissions are desired for the intermediate directories, they can be changed afterwards with chmod.

Note that some of the requested directories may have been created even if an error occurs.


The System V -m option was included to control the file mode.

The System V -p option was included to create any needed intermediate directories and to complement the functionality provided by rmdir for removing directories in the path prefix as they become empty. Because no error is produced if any path component already exists, the -p option is also useful to ensure that a particular directory exists.

The functionality of mkdir is described substantially through a reference to the mkdir() function in the System Interfaces volume of POSIX.1‐2017. For example, by default, the mode of the directory is affected by the file mode creation mask in accordance with the specified behavior of the mkdir() function. In this way, there is less duplication of effort required for describing details of the directory creation.


chmod, rm, rmdir, umask

The Base Definitions volume of POSIX.1‐2017, Chapter 8, Environment Variables, Section 12.2, Utility Syntax Guidelines

The System Interfaces volume of POSIX.1‐2017, mkdir(), umask()

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at .

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2017 IEEE/The Open Group