MKNOD(8) BSD System Manager's Manual MKNOD(8)
mknod -- make device special file
mknod [-rR] [-F fmt] [-g gid] [-m mode] [-u uid] name [c | b] major minor
mknod [-rR] [-F fmt] [-g gid] [-m mode] [-u uid] name [c | b] major unit
mknod [-rR] [-g gid] [-m mode] [-u uid] name [c | b] number
mknod [-rR] [-g gid] [-m mode] [-u uid] name p
The mknod command creates device special files, or fifos. Normally the
shell script /dev/MAKEDEV is used to create special files for commonly
known devices; it executes mknod with the appropriate arguments and can
make all the files required for the device.
To make nodes manually, the arguments are:
-r Replace an existing file if its type is incorrect.
-R Replace an existing file if its type is incorrect. Correct the
mode, user and group.
-F fmt Create device nodes that may be used by an operating system
which uses device numbers packed in a different format than
NetBSD uses. This is necessary when NetBSD is used as an NFS
server for netbooted computers running other operating systems.
The following values for the fmt are recognized: native, 386bsd,
4bsd, bsdos, freebsd, hpux, isc, linux, netbsd, osf1, sco,
solaris, sunos, svr3, svr4, and ultrix.
-g gid Specify the group for the device node. The gid operand may be a
numeric group ID or a group name. If a group name is also a
numeric group ID, the operand is used as a group name. Precede
a numeric group ID with a # to stop it being treated as a name.
-m mode Specify the mode for the device node. The mode may be absolute
or symbolic, see chmod(1).
-u uid Specify the user for the device node. The uid operand may be 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. Precede a
numeric user ID with a # to stop it being treated as a name.
name Device name, for example ``sd'' for a SCSI disk on an HP300 or a
``pty'' for pseudo-devices.
b | c | p
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.
Specifying p creates fifo files.
major The major device number is an integer number which tells the
kernel which device driver entry point to use. To find out
which major device number to use for a particular device, check
the file /dev/MAKEDEV to see if the device is known, or check
the system dependent device configuration file:
minor The minor device number tells the kernel which one of several
similar devices the node corresponds to; for example, it may be
a specific serial port or pty.
unit and subunit
The unit and subunit numbers select a subset of a device; for
example, the unit may specify a particular SCSI disk, and the
subunit a partition on that disk. (Currently this form of spec-
ification is only supported by the bsdos format, for compatibil-
ity with the BSD/OS mknod).
number A single opaque device number. Useful for netbooted computers
which require device numbers packed in a format that isn't sup-
ported by -F.
chmod(1), mkfifo(1), mkfifo(2), mknod(2), MAKEDEV(8)
A mknod command appeared in Version 6 AT&T UNIX. The -F option appeared
in NetBSD 1.4. The -g, -m, -r, -R, and -u options appeared in
BSD May 8, 2003 BSD