Article · Wikipedia archive · Last revised Jul 16, 2026

Indent (Unix)

indent is a Unix utility that reformats C and C++ code in a user-defined indentation style and coding style. Support for C++ code is minimal.

Last revised
Jul 16, 2026
Read time
≈ 1 min
Length
246 w
Citations
6
Source
Wikipedia ↗
indent
Original authorDavid Willcox
DevelopersDavid Ingamells, Carlo Wood, Joseph Arceneaux, Jim Kingdon, John Bridges
ReleaseNovember 1976 (1976-11)
Stable release
2.2.131 / 20 March 2023 (20 March 2023)
Written inC
Operating systemCross-platform
Typesource-code-reformat tool
LicenseGNU: GPL-3.0-or-later2
WebsiteGNU: gnu.org/software/indent/
Repository

indent is a Unix utility that reformats C and C++ code in a user-defined indentation style and coding style. Support for C++ code is minimal.3

The original version of indent was written by David Willcox at the University of Illinois in November 1976. It was incorporated into 4.1BSD in October 1982.4 GNU indent was first written by Jim Kingdon in 1989. The command is available as a separate package for Microsoft Windows as part of the UnxUtils collection of native Win32 ports of common GNU Unix-like utilities.5

Examples of usage

The following command 

$ indent -st -bap -bli0 -i4 -l79 -ncs -npcs -npsl -fca -lc79 -fc1 -ts4 some_file.c

indents some_file.c in a style resembling BSD/Allman style and writes the result to the standard output.

GNU indent

GNU indent is the GNU Project's version of indent. A different indentation style, the GNU style, is used by default.6

References

References

  1. "NEWS - indent.git". Retrieved 16 May 2023.
  2. GNU Savannah. "GNU indent". Retrieved 2023-10-30. License: GNU General Public License v3 or later
  3. "indent: Indent and Format C Program Source". www.gnu.org. Retrieved 2019-08-16.
  4. Dickey, Thomas (2017). "CINDENT - C-language formatter". Invisible Island. Retrieved 2019-04-22.
  5. "Native Win32 ports of some GNU utilities". unxutils.sourceforge.net.
  6. GNU Indent Manual
External links