MKFIFO(1M) Maintenance Commands MKFIFO(1M)

mkfifo - make FIFO special file

/usr/bin/mkfifo [-m mode] file...

mkfifo [ options ] file...

The mkfifo utility creates the FIFO special files named by its argument list. The arguments are taken sequentially, in the order specified; and each FIFO special file is either created completely or, in the case of an error or signal, not created at all.

If errors are encountered in creating one of the special files, mkfifo writes a diagnostic message to standard error and continues with the remaining arguments, if any.

The mkfifo utility calls the library routine mkfifo(3C), with a path argument equivalent to the file argument from the command line, and mode is set to the equivalent of a=rw, modified by the current value of the file mode creation mask umask(1).

The mkfifo utility creates one or more FIFOs. By default, the mode of the created FIFO is a=rw minus the bits set in umask(1).

The following option is supported for /usr/bin/mkfifo:

-m mode

Set the file permission bits of the newly-created FIFO to the specified mode value. The mode option-argument will be the same as the mode operand defined for the chmod(1) command. For a symbolic mode option-argument, the op characters + and will be interpreted relative to an assumed initial mode of a=rw.

The following option is supported for ksh93:

-m mode

Set the mode of the created FIFO to mode. The mode option-argument is a symbolic or octal mode as in chmod(1). Relative modes assume an initial mode of a=rw.

The following operand is supported:


A path name of the FIFO special file to be created.

See largefile(5) for the description of the behavior of mkfifo when encountering files greater than or equal to 2 Gbyte ( 2^31 bytes).

See environ(5) for descriptions of the following environment variables that affect the execution of mkfifo: LANG, LC_ALL, LC_CTYPE, LC_MESSAGES, and NLSPATH.

The following exit values are returned:


All the specified FIFO special files were created successfully.


An error occurred.

See attributes(5) for descriptions of the following attributes:

Interface Stability Standard

chmod(1), umask(1), mkfifo(3C), attributes(5), environ(5), largefile(5), standards(5)
June 24, 2020 OmniOS