Linux/command/mknod

computing: software: operating systems: Linux: mknod

Questions

• What happens if mknod is invoked with just a name and no options, as in "mknod /dev/loop0"?

Manpage

Name

• mknod - make block or character special files

Synopsis

• mknod [OPTION]... NAME TYPE [MAJOR MINOR]

Description

Create the special file NAME of the given TYPE. TYPE can be a FIFO, character special file, or block special file. An exit status of zero indicates success, and a nonzero value indicates failure

The term "special file" (not to be confused with "Special File Type") 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.

Mandatory arguments to long options are mandatory for short options too.

• -m, --mode=MODE

set permission mode (as in chmod), not a=rw -umask. Uses `a=rw' minus the bits set in the umask as

the point of departure. (Editor's note: these last two bits of information seem to flatly contradict each other; the first is from MAN, the second is from info. It's also unclear.)

• --help

display this help and exit

• --version

output version information and exit Both MAJOR and MINOR must be specified when TYPE is b, c, or u (i.e. the special file is block or character type), and they must be omitted when TYPE is p. If MAJOR or MINOR begins with 0x or 0X, it is interpreted as hexadecimal; otherwise, if it begins with 0, as octal; otherwise, as decimal.

TYPE may be:

• b

  create a block (buffered) special file

• c, u

  create a character (unbuffered) special file

• p

  create a FIFO

Author

Written by David MacKenzie.

Reporting Bugs

Report bugs to <bug-coreutils@gnu.org>.

Copyright

Copyright © 2004 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

See Also

The full documentation for mknod is maintained as a Texinfo manual. If the info and mknod programs are properly installed at your site, the command info coreutils mknod should give you access to the complete manual.

Edit History

• 2005-10-14 Cleaned up after being imported into htyp
• 2005-06-25 This page created from a combination of MAN page and info coreutils (both in Ubuntu hoary).