mknod

Create a block device special file

$ sudo mknod [path/to/device_file] b [major_device_number] [minor_device_number]

$ sudo mknod [path/to/device_file] c [major_device_number] [minor_device_number]

$ sudo mknod [path/to/device_file] p

$ sudo mknod -m [0660] [path/to/device_file] c [major] [minor]

$ sudo mknod -Z [path/to/device_file] c [major] [minor]

mknod [-m mode] [-Z] [--context[=ctx]] name type [major minor]

mknod creates block devices, character devices, or FIFOs (named pipes) as special files. Device files provide an interface between user programs and device drivers in the kernel.
Block devices transfer data in fixed-size blocks and support buffering (e.g., hard drives). Character devices transfer data character by character without buffering (e.g., terminals, serial ports). FIFOs enable inter-process communication through a named file.
Major and minor numbers identify the device driver and specific device instance. These numbers can be specified in decimal, octal (prefix 0), or hexadecimal (prefix 0x).

-m, --mode _mode_

Set file permission bits instead of default (a=rw minus umask)

Apply default SELinux security context

Set SELinux or SMACK security context to specified value

Create block (buffered) special file; requires major and minor numbers

Create character (unbuffered) special file; requires major and minor numbers

Create FIFO (named pipe); major and minor must be omitted

Modern Linux systems use udev and devtmpfs for dynamic device node creation, making manual mknod usage rare. Creating device nodes requires root privileges. Incorrect major/minor numbers can cause system instability. The /dev directory is typically mounted as devtmpfs and managed automatically.

mknod is a standard Unix command dating back to early Unix systems. It is part of GNU coreutils on Linux. The command provides direct access to the mknod(2) system call for creating special files.

mkfifo(1), stat(2), mknod(2)