Microsoft KB Archive/101875

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How to Enable ANSI.SYS in a Command Window

Article ID: 101875

Article Last Modified on 11/1/2006


  • Microsoft Windows NT Advanced Server 3.1
  • Microsoft Windows NT Server 3.5
  • Microsoft Windows NT Server 3.51
  • Microsoft Windows NT Server 4.0 Standard Edition
  • Microsoft Windows NT Workstation 3.1
  • Microsoft Windows NT Workstation 3.5
  • Microsoft Windows NT Workstation 3.51
  • Microsoft Windows NT Workstation 4.0 Developer Edition

This article was previously published under Q101875


ANSI.SYS can be loaded and used from the command prompt, with the restriction that it can run only in the context of the MS-DOS subsystem. Windows NT does not support ANSI escape sequences in Win32 Console applications. To load ANSI.SYS, add "device=c:\winnt\system32\ansi.sys" to the CONFIG.NT file in the Windows NT SYSTEM32 directory.


Once ANSI.SYS is loaded, you can use any MS-DOS-based program that makes use of this driver. However, if you want to use ANSI.SYS to change the look of the command prompt, you may have to perform some additional steps.

For example, to highlight the prompt in MS-DOS command prompt, you must add "dosonly" to your CONFIG.NT file, and run COMMAND (not CMD) from MS-DOS Command Prompt. You can then run a batch file that includes the PROMPT command with ANSI escape sequences to highlight the prompt.

NOTE: While this gives the command prompt the same appearance as an MS-DOS prompt, you are now in a DOS-based command prompt, and you can no longer start non-DOS programs from the command line.

ANSI.SYS, being an MS-DOS-based device driver, can be used only in the context of the MS-DOS subsystem.

VT52.SYS may be used in the same manner as ANSI.SYS, with the same restrictions.

Additional query words: prodnt

Keywords: kbhowto kbinterop KB101875