The mknod command shall create a special file named name of the given type.
The type shall be one of the following:
creates a block (buffered) special file with the specified major and minor device numbers.
creates a character (unbuffered) special file with the specified major and minor device numbers.
creates a FIFO.
|-m mode, --mode=mode|
create the special file with file access permissions set as described in mode. The permissions may be any absolute value (i.e. one not containing '+' or '-') acceptable to the chmod command.
output version information and exit.
If type is p, major and minor shall not be specified. Otherwise, these parameters are mandatory.
This command may be deprecated in a future version of this specification. The major and minor operands are insufficently portable to be specified usefully here. Only a FIFO can be portably created by this command, and the mkfifo command is a simpler interface for that purpose.