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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][--version][--]

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 synonym 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.

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.

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

       --version
              Print version information on standard output, then exit success-
              fully.

       --     Terminate option list.

CONFORMINGTO
       POSIX does not describe this command as it is nonportable,  and  recom-
       mends  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 fileutils-4.0 package;
       other  versions may differ slightly.  Mail corrections and additions to
       aebcwi.nl.    Report   bugs   in    the    program    to    fileutils-
       bugsgnu.edu.

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




GNU fileutils 4.0                   1998-11                           MKNOD(1)