Article · Wikipedia archive · Last revised May 28, 2026

Comp (command)

In computing, comp is a command used on DEC OS/8, DOS, DR FlexOS, IBM OS/2, Microsoft Windows and related computer operating systems such as ReactOS. It is used to perform comparisons of multiple computer files to show the differences between them.

Last revised
May 28, 2026
Read time
≈ 2 min
Length
457 w
Citations
12
Source
Wikipedia ↗
comp
DevelopersDEC, IBM, Microsoft, Digital Research, Novell, Paul Vojta, ReactOS Contributors
Initial releaseAugust 1981 (1981-08)
Operating systemOS/8, PC DOS, MS-DOS, FlexOS, SISNE plus, OS/2, eComStation, ArcaOS, Windows, DR DOS, FreeDOS, ReactOS
PlatformCross-platform
TypeCommand
LicenseFreeDOS: MIT
ReactOS: GNU GPL 2

In computing, comp is a command used on DEC OS/8,1 DOS,2 DR FlexOS,3 IBM OS/2,4 Microsoft Windows5 and related computer operating systems such as ReactOS. It is used to perform comparisons of multiple computer files to show the differences between them.6

History

COMP.COM (among other commands) in IBM PC DOS 1.0. source ↗

In DOS, the comp command first appeared in PC DOS 1.07 and has been included in most versions of MS-DOS and PC DOS. A newer command, fc was added in DOS 3.3 which allows for line comparisons in addition to binary comparisons. DR DOS 6.0 also includes an implementation of the comp command.8

The FreeDOS version was developed by Paul Vojta and is licensed under the MIT License.9 Ged Murphy developed the ReactOS version. It is licensed under the GNU GPL 2.10

The command is also available in the EFI shell.11

Syntax

The command-syntax is:12 

comp [<Data1>] [<Data2>] [/d] [/a] [/l] [/n=<Number>] [/c]

Parameters

  • <Data1> – Location and name of the first file or set of files
  • <Data2> – Location and name of the second file or set of files
  • /d – Display differences in decimal format (Default is hexadecimal)
  • /a – Display differences as characters
  • /l – Display the number of the line, instead of the byte offset
  • /n=<Number> – Compare only the specified number of lines for each file
  • /c – Perform a non case-sensitive comparison
  • /off[line] – Process files with the offline attribute set
  • /? – Display Help
See also

See also

References

References

  1. "Concise Command Language" (CCL)."OS/8 Handbook" (PDF). April 1974. Retrieved 28 November 2017.
  2. Jamsa, Kris A. (1993), DOS: The Complete Reference, Osborne McGraw-Hill, p. 206, ISBN 0078819040.
  3. http://www.bitsavers.org/pdf/digitalResearch/flexos/1073-2003_FlexOS_Users_Guide_V1.3_Nov86.pdf Archived 2019-09-25 at the Wayback Machine
  4. "OS/2 Commands". www.jatomes.com. Archived from the original on 2019-04-14. Retrieved 2019-07-20.
  5. "Comp".
  6. Wolverton, Van (2003). Running MS-DOS Version 6.22 (20th Anniversary Edition), 6th Revised edition. Microsoft Press. ISBN 0-7356-1812-7.
  7. http://www.bitsavers.org/pdf/ibm/pc/dos/6172220_DOS_1.0_Jan82.pdf
  8. "DR DOS 6.0 User Guide Optimisation and Configuration Tips" (PDF). Archived from the original (PDF) on 2019-09-30. Retrieved 2019-08-13.
  9. "FreeDOS 1.2 Updates Package - comp (FreeDOS Base)". Ibiblio.org. 2006-10-21. Retrieved 2022-09-04.
  10. "Reactos/Reactos". GitHub. 3 January 2022.
  11. "EFI Shells and Scripting". Intel. Archived from the original on 2009-01-30. Retrieved 2013-09-25.
  12. MS-DOS and Windows command line comp command
Further reading

Further reading

External links