China DOS Union

Has anyone written about this? :-)
When writing a batch file, if a lot of errorlevels are unclear, what do you do?
Enter command /z, and then the errorlevel of external commands you run later
can be seen.

Everybody knows that...

Re polynominal:

Unfortunately DOS 6.x and below do not support it. Right now I am working on a high-efficiency BATCH for obtaining ERRORLEVEL. Without the problem I mentioned, it can be finished very quickly.

Re Wengier:

Isn't that a bit too absolute?

The following is quoted from willsort's post on 2004-2-3 13:40:21:
Re polynominal:

    Unfortunately DOS 6.x and below do not support it. Right now I am working on a high-efficiency BATCH for obtaining ERRORLEVEL. Without the problem I mentioned, it can be finished very quickly.

This is it:
:: Author: Leonardo Pignataro (secret_doom@hotmail.com)
:: Trace errorlevel
@echo off
for %%? in (0 1 2) do if errorlevel=%%?00 set D1=%%?
for %%? in (0 1 2 3 4 5 6 7 8 9) do if errorlevel=%D1%%%?0 set D2=%%?
for %%? in (0 1 2 3 4 5 6 7 8 9) do if errorlevel=%D1%%D2%%%? set D3=%%?
set err=%D1%%D2%%D3%
for %%? in (D1 D2 D3) do set %%?=
echo %err%

Re roy:

Nice idea, it can serve as a reference for me to finish the next post. Just one thing: could you please not use = after IF ERRORLEVEL? It deepens misunderstanding.

http://model.chinajewelry.net/dos/dosbbs/dispbbs.asp?boardID=6&ID=9358

willsort：

As for COMMAND /Z, because I had introduced it on the website before as an undocumented DOS usage, that is why I thought everyone should already know it.

Actually ERR2ENV may be easier to use.

As for DOS 6.x and below, then it has no real meaning. Those old DOS versions no longer have much practical value, and of course they do not support these new features either.

The following is quoted from willsort's post on 2004-2-3 20:29:42:
Reroy:

Nice idea, it can serve as a reference for me to finish the next post. Just one thing: could you please not use = after IFERRORLEVEL? It deepens misunderstanding.

http://model.chinajewelry.net/dos/dosbbs/dispbbs.asp?boardID=6&ID=9358

ERRORLEVEL is a variable, just like %COMSPEC%, so "=" can be used.

What's more, the one who's wrong isn't me, it's Leonardo Pignataro.

Roy: That's not right. This isn't under the WinNT/2K/XP "command prompt interface." Under pure DOS, ERRORLEVEL is not a variable, but a special usage of IF, namely: IF ERRORLEVEL ...

Re Wengier:

People nowadays collect a lot of valuable materials, but study little of them. Many people only come to the forum to ask when they actually need something. So the spread of information does not lie in whether it is public, but in whether the audience has the desire to learn about it.

Re Roy:

What Wengier said is quite right: errorlevel is used as an if command branch. Even under 98 and xp I have never seen this environment variable. And if this ERRORLEVEL were an environment variable, then this program itself would lose its meaning, because the purpose of the program is to assign the ERRORLEVEL value to an environment variable. Even if we assume Leonardo Pig was using it as a variable, then he should have used ==; otherwise it would be a syntax error. So here we can be sure he was using it as a command branch.

And when used as a command branch, the relationship between ERRORLEVEL and value should be greater than or equal to, not equal, so that is why I said = is somewhat misleading. Then why can = still be used? Because ERRORLEVEL and value are originally separated by a space, and the DOS command line ignores a single = when parsing. This is the same as ; and a space. If you don't believe it, you can do a test.

::test.bat
echo First:%1
echo Second:%2

c:\test 111 222
c:\test 111;222
c:\test 111=222

Also, there are many characters in the DOS command line that get special interpretation. Everyone can test more of them. Redirect symbols are too familiar, so I'll skip them

Why is there no response when I type it under Windows 2000?
Under commnad or under cmd
typing COMMAND /Z just jumps to the next line