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I have an install of Windows XP SP3 OEM that I use often. Recently its cmd.exe somehow forgot that pressing TAB means I want to use the completion feature.

I found out how to fix this problem here, and it worked just fine.

Cause for concern:

I was surprised and confused by what the completion character was set to.

The completion character was set to the ASCII SUB character, 0x1a, or 26.

My questions:

  1. What is the ASCII SUB character, 0x1a, or 26, used for? Can I type it? Can I type it in one keystroke?
  2. What could have caused it to be set to anything else that the ASCII TAB character, 0x09, or 9?
share|improve this question
Interesting, +1. – John T Feb 16 '10 at 17:48
up vote 4 down vote accepted

In the context of the Windows command prompt, ASCII 26 represents an end of file character. You can type it in the command prompt by holding and releasing Alt + 2 + 6 (in that order) or Ctrl + z. It will produce ^Z (Control-Z). In other applications, you will see a right-facing arrow with the Alt combination, and the Ctrl combination likely performs an undo operation, depending on the software.

I haven't personally seen this behavior, maybe some software you installed had altered it. A very interesting problem though nonetheless!

share|improve this answer
What a pain! Although Control-Z is much shorter than Alt+Fn+K followed by Alt+Fn+O on my laptop, I'll just leave it as Tab. Thanks! – eleven81 Feb 16 '10 at 17:56
Glad you got things sorted out, you're more than welcome :) – John T Feb 16 '10 at 17:59

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