Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages


home | help
MKNOD(8)                FreeBSD System Manager's Manual               MKNOD(8)

     mknod -- build special file

     mknod name [b | c] major minor [owner:group]

     The mknod utility is deprecated on modern FreeBSD systems.

     The mknod utility creates device special files.  To make nodes manually,
     the four required arguments are:

     name    Device name, for example ``sd'' for a SCSI disk on an HP300 or a
             ``pty'' for pseudo-terminals.

     b | c   Type of device.  If the device is a block type device such as a
             tape or disk drive which needs both cooked and raw special files,
             the type is b.  All other devices are character type devices,
             such as terminal and pseudo devices, and are type c.

     major   The major device number is an integer number which tells the ker-
             nel which device driver entry point to use.  To learn what major
             device number to use for a particular device, check

     minor   The minor device number tells the kernel which subunit the node
             corresponds to on the device; for example, a subunit may be a
             file system partition or a tty line.

             The owner group operand pair is optional, however, if one is
             specified, they both must be specified.  The owner may be either
             a numeric user ID or a user name.  If a user name is also a
             numeric user ID, the operand is used as a user name.  The group
             may be either a numeric group ID or a group name.  Similar to the
             user name, if a group name is also a numeric group ID, the oper-
             and is used as a group name.

     Major and minor device numbers can be given in any format acceptable to
     strtoul(3), so that a leading `0x' indicates a hexadecimal number, and a
     leading `0' will cause the number to be interpreted as octal.

     The mknod utility can be used to recreate deleted device nodes under a
     devfs(5) mount point by invoking it using dummy arguments.  Example:

           mknod cd0 c 0 0

     where ``cd0'' is the name of the deleted device node.

     The chown(8)-like functionality is specific to FreeBSD.

     As of FreeBSD 4.0, block devices were deprecated in favour of character
     devices.  As of FreeBSD 5.0, device nodes are managed by the device file
     system devfs(5), making the mknod utility superfluous.  As of FreeBSD 6.0
     device nodes may be created in regular file systems but such nodes cannot
     be used to access devices.

     mkfifo(1), mknod(2), devfs(5), chown(8)

     A mknod utility appeared in Version 6 AT&T UNIX.

FreeBSD 6.2                    December 15, 2004                   FreeBSD 6.2


Want to link to this manual page? Use this URL:

home | help