MKNOD(1)                                                 MKNOD(1)



NAME

       mknod - make block or character special files


SYNOPSIS

       mknod [options] name {bc} major minor
       mknod [options] name p

       GNU  options  (shortest  form): [-m mode] [--help] [--ver-
       sion] [--]


DESCRIPTION

       mknod creates a FIFO (named pipe), character special file,
       or block special file with the specified name.

       A  special  file  is  a triple (boolean, integer, integer)
       stored in the filesystem.   The  boolean  chooses  between
       character  special  file  and  block special file. The two
       integers are the major and minor device number.

       Thus, a special file takes almost no place on disk, and is
       used only for communication with the operating system, not
       for data storage. Often special files  refer  to  hardware
       devices  (disk, tape, tty, printer) or to operating system
       services (/dev/null, /dev/random).

       Block special files usually are disk-like  devices  (where
       data  can be accessed given a block number, and e.g. it is
       meaningful to have a block cache).  All other devices  are
       character  special files.  (Long ago the distinction was a
       different one: I/O to a character special  file  would  be
       unbuffered, to a block special file buffered.)

       The mknod command is what creates files of this type.

       The  argument following name specifies the type of file to
       make:

              p      for a FIFO

              b      for a block (buffered) special file

              c      for a character (unbuffered) special file

       The GNU version of mknod allows u (`unbuffered') as a syn-
       onym for c.

       When  making  a block or character special file, the major
       and minor device numbers must be given after the file type
       (in  decimal,  or in octal with leading 0; the GNU version
       also allows hexadecimal with leading 0x).  By default, the
       mode  of created files is 0666 (`a+rw') minus the bits set
       in the umask.





GNU fileutils 4.0         November 1998                         1





MKNOD(1)                                                 MKNOD(1)



OPTIONS

       -m mode, --mode=mode
              Set the mode of created files to mode, which can be
              symbolic  as  in chmod(1) and then uses the default
              mode as the point of departure.


GNU STANDARD OPTIONS

       --help Print a usage message on standard output  and  exit
              successfully.

       --version
              Print  version information on standard output, then
              exit successfully.

       --     Terminate option list.


CONFORMING TO

       POSIX does not describe this command as it is nonportable,
       and  recommends using mkfifo(1) to make FIFOs.  SVID has a
       command /etc/mknod with the above syntax, but without  the
       mode option.


NOTES

       On  a  Linux  system  (version  1.3.22  or newer) the file
       /usr/src/linux/Documentation/devices.tex contains  a  list
       of devices with device name, type, major and minor number.

       The present page describes mknod as found  in  the  fileu-
       tils-4.0  package;  other  versions  may  differ slightly.
       Mail corrections and additions to aeb@cwi.nl.  Report bugs
       in the program to fileutils-bugs@gnu.ai.mit.edu.


SEE ALSO

       chmod(1), mkfifo(1), mknod(2)























GNU fileutils 4.0         November 1998                         2