Gnu/coreutils/mknod-invocation
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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 disk. (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
(i.e., env mknod …
) to avoid interference
from the shell.
The arguments after name
specify the type of file to make:
- ‘
p
’ for a FIFO
- ‘
b
’ for a block special file
- ‘
c
’ 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.
- ‘
-m mode
’
‘--mode=mode
’ Set the mode of created files to
mode
, which is symbolic as inchmod
and uses ‘a=rw
’ as the point of departure.mode
should specify only file permission bits. See File permissions.- ‘
-Z
’
‘--context[=context]
’ Without a specified
context
, adjust the SELinux security context according to the system default type for destination files, similarly to therestorecon
command. 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.
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