mknod invocation (GNU Coreutils 9.0)
12.5 mknod: Make block or character special files
mknod creates a FIFO, character special file, or block special file with the specified name. Synopsis:
mknod [option]… name type [major minor]
Unlike the phrase “special file type” above, the term special file has a technical meaning on Unix: something that can generate or receive data. Usually this corresponds to a physical piece of hardware, e.g., a printer or a flash drive. (These files are typically created at system-configuration time.) The
mknod command is what creates files of this type. Such devices can be read either a character at a time or a “block” (many characters) at a time, hence we say there are block special files and character special files.
Due to shell aliases and built-in
mknod functions, using an unadorned
mknod interactively or in a script may get you different functionality than that described here. Invoke it via
env mknod …) to avoid interference from the shell.
The arguments after
name specify the type of file to make:
for a FIFO
for a block special file
for a character special file
When making a block or character special file, the major and minor device numbers must be given after the file type. If a major or minor device number begins with ‘
0x’ or ‘
0X’, it is interpreted as hexadecimal; otherwise, if it begins with ‘
0’, as octal; otherwise, as decimal.
The program accepts the following options. Also see Common options.
Set the mode of created files to
mode, which is symbolic as in
chmodand uses ‘
a=rw’ as the point of departure.
modeshould specify only file permission bits. See File permissions.
Without a specified
context, adjust the SELinux security context according to the system default type for destination files, similarly to the
restoreconcommand. The long form of this option with a specific context specified, will set the context for newly created files only. With a specified context, if both SELinux and SMACK are disabled, a warning is issued.
An exit status of zero indicates success, and a nonzero value indicates failure.