device special files
command creates device special files.
Normally the shell script /dev/MAKEDEV
is used to
create special files for commonly known devices; it executes
with the appropriate arguments and can make
all the files required for the device.
The options are as follows:
- Set the file permission bits of newly created device
special files to mode. The mode argument
can be in any of the formats specified to the
chmod(1) utility. If a
symbolic mode is specified, the operators
-’ are interpreted relative to an
initial mode of “a=rw”.
To make nodes manually, the arguments are:
- Device or FIFO name. For example “sd” for a
SCSI disk or a “pty” for pseudo-devices. FIFOs may be named
arbitrarily by the user.
| c |
- Type of device or FIFO. 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. A FIFO (also known as a named
pipe) is type p.
- The major device number is an integer number which tells
the kernel which device driver entry point to use. To learn what major
device number to use for a particular device, check the file
/dev/MAKEDEV to see if the device is
- The minor device number tells the kernel which subunit the
node corresponds to on the device; for example, a subunit may be a
filesystem partition or a tty line.
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.
As an extension, mknod
can also take multiple lists
of parameters in one go. Note that -m
reset from one list to the next so, for example, in
mknod -m 700 name b 12 5 name2 b 12
will be mode 700.
command appeared in
Version 4 AT&T UNIX