Make FIFO special files (POSIX)
mkfifo [-p] [-m mode] file...
The mode option argument is a symbolic_mode string, as defined for the chmod utility. In the symbolic_mode strings, the op characters + and - are interpreted relative to the default file mode for that file type, as follows:
The mkfifo utility creates the FIFO special files specified by the file operands in the order they're specified.
To create a FIFO in a directory, you must have write permission for that directory or be logged in as root.
The default file mode for FIFO files is a=rw (666) with selected permissions removed in accordance with the file mode creation mask (see umask). For intermediate pathname components created by mkfifo, the mode is the default modified by u+wx so that any subdirectories and the FIFO file can always be created regardless of the file mode creation mask. If you wish to assign different ultimate permissions for the intermediate directories, you can change these permissions afterward with the chmod utility.
If the mkfifo utility is terminated by a signal, some of the specified FIFO special files or intermediate directories might have already been created, and may not be automatically removed.
chmod, ln, mkdir, touch