PROLOG

       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.

NAME

       mkfifo — make FIFO special files

SYNOPSIS

       mkfifo [−m mode] file...

DESCRIPTION

       The mkfifo utility shall create the FIFO special files specified by the operands, in the order specified.

       For  each  file  operand,  the  mkfifo  utility shall perform actions equivalent to the mkfifo() function
       defined in the System Interfaces volume of POSIX.1‐2008, called with the following arguments:

        1. The file operand is used as the path argument.

        2. The value of the bitwise-inclusive OR of S_IRUSR, S_IWUSR, S_IRGRP, S_IWGRP, S_IROTH, and S_IWOTH  is
           used as the mode argument. (If the −m option is specified, the value of the mkfifo() mode argument is
           unspecified, but the FIFO shall at no time have permissions less restrictive than the −m mode option-
           argument.)

OPTIONS

       The  mkfifo  utility  shall conform to the Base Definitions volume of POSIX.1‐2008, Section 12.2, Utility
       Syntax Guidelines.

       The following option shall be supported:

       −m mode   Set the file permission bits of the newly-created FIFO 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=rw.

OPERANDS

       The following operand shall be supported:

       file      A pathname of the FIFO special file to be created.

STDIN

       Not used.

INPUT FILES

       None.

ENVIRONMENT VARIABLES

       The following environment variables shall affect the execution of mkfifo:

       LANG      Provide a default value for the internationalization variables that are unset or null. (See the
                 Base Definitions volume of POSIX.1‐2008, Section 8.2, Internationalization  Variables  for  the
                 precedence   of   internationalization  variables  used  to  determine  the  values  of  locale
                 categories.)

       LC_ALL    If set to a non-empty string value, override the values of all the  other  internationalization
                 variables.

       LC_CTYPE  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).

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

       NLSPATH   Determine the location of message catalogs for the processing of LC_MESSAGES.

ASYNCHRONOUS EVENTS

       Default.

STDOUT

       Not used.

STDERR

       The standard error shall be used only for diagnostic messages.

OUTPUT FILES

       None.

EXTENDED DESCRIPTION

       None.

EXIT STATUS

       The following exit values shall be returned:

        0    All the specified FIFO special files were created successfully.

       >0    An error occurred.

CONSEQUENCES OF ERRORS

       Default.

       The following sections are informative.

APPLICATION USAGE

       None.

EXAMPLES

       None.

RATIONALE

       This utility was added to permit shell applications to create FIFO special files.

       The −m option was added to control the file mode, for consistency with the similar functionality provided
       by the mkdir utility.

       Early proposals included a −p option similar to the mkdir −p option that created intermediate directories
       leading  up  to  the  FIFO  specified by the final component. This was removed because it is not commonly
       needed and is not common practice with similar utilities.

       The functionality of mkfifo is described substantially through a reference to the  mkfifo()  function  in
       the  System  Interfaces  volume  of  POSIX.1‐2008.  For example, by default, the mode of the FIFO file is
       affected by the file mode creation mask in  accordance  with  the  specified  behavior  of  the  mkfifo()
       function.  In  this  way, there is less duplication of effort required for describing details of the file
       creation.

FUTURE DIRECTIONS

       None.

SEE ALSO

       chmod, umask

       The Base Definitions volume of POSIX.1‐2008, Chapter 8,  Environment  Variables,  Section  12.2,  Utility
       Syntax Guidelines

       The System Interfaces volume of POSIX.1‐2008, mkfifo()

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition,
       Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open  Group  Base
       Specifications  Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc
       and The Open Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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
       http://www.unix.org/online.html .

       Any  typographical  or formatting errors that appear in this page are most likely to have been introduced
       during  the  conversion  of  the  source  files  to  man  page  format.  To  report  such   errors,   see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .