Cmd.exe bug with special characters

[xpdev]

I have a batch file called

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`#'`#!^% ^%os%'&!&(.bat

with the following:

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@echo off
echo Test
echo %0
echo Test 2

If I escape the characters like this:

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set p=%
"`#'`#!^%p% ^%p%os%p%'&!&(.bat"

Then every command works.
But if I escape them like this:

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`#'`#!^^^%" "^^^%os^%'^&!^&^(.bat

Then only the first command works. The batch file exits after that. Why does this bug happen?

[jfl]

This is because %0 is the command string you typed, not the actual script name.
In the first case, it's quoted, so the special characters do not confuse the echo command.
In the second case, it's not quoted, and the special & and ( characters (which have lost their protecting ^ at this stage) do confuse it.

It would fail in both cases if you used %~0 instead of %0, thereby eliminating quotes in both cases.
Conversely, "%~0" would make it work in both cases.

[jeb]

Hi,

as JFL already said, the echo %0 is the problem.

If you want to see the content without problems, you could use the REM technique.

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@echo off
echo Test

echo on
REM # %0 #
@echo off

echo Test 2