China DOS Union

Environment: XP Below is the result when I run
C:\>set t=abc & echo %t%
%t%

C:\>set t=abc & echo %t%
abc
The first time I ran it, the value of the variable was not displayed. I tried to write the two sentences separately and save them as a bat file, and I could get the result normally. But I don't know why the one connected by & can't get the expected result, so that when I run Brother Wunaikai's signature, I get such a result.
C:\>%ComSpec% /cset,=^G何奈无──　。何奈可无是原，事奈无做人奈无^G&for,/l,%i,in,(22,-1,0)do,@call,set/p= %,:~%i,1%<nul&ping/n 1 127.1>nul
%,:~22,1% %,:~21,1% %,:~20,1% %,:~19,1% %,:~18,1% %,:~17,1% %,:~16,1% %,:~15,1%
%,:~14,1% %,:~13,1% %,:~12,1% %,:~11,1% %,:~10,1% %,:~9,1% %,:~8,1% %,:~7,1% %,
:~6,1% %,:~5,1% %,:~4,1% %,:~3,1% %,:~2,1% %,:~1,1% %,:~0,1%
Is there any solution?
Also, there is one point I don't understand above, why does he use call?
[ Last edited by 0401 on 2005-12-2 at 09:29 ]

Re 0401:

The signature of Wunaike has clearly indicated that this long code is used in the Start Run, not in the command line environment. In the command line, you need to remove the leading %comspec% /c and only keep the content from set,= onwards.

As for set & echo, it originates from a delayed effect of variable substitution. That is to say, the variable set in one statement can be correctly referenced in the next statement. The existence of this delayed effect is due to the shared problem of the command line environment space, which is relatively complicated to talk about in detail. You can refer to cmd /? for relevant instructions.

And the for in the signature actually calls and executes the same statement multiple times. , and plus using ping for intentional delay, which creates the effect of characters appearing one by one; in addition, the delay time of ping /n 1 127.1 running at different times here is different, which should be related to the IP address 127.1, and it has not been finally determined.


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[ Last edited by willsort on 2006-1-21 at 22:50 ]

Thanks to the hint from user willsort, I seem to understand something, but I still don't know why when I use "set t=abc & echo %t%", the first time I get "%t%" instead of "abc". Is it that the two statements are executed together instead of the statement before "&" being executed first and then the one after?

Re 0401:

Sorry! I didn't notice your reply in time and made some supplements to the issues you mentioned in the original post.

The role is to make the variable that takes part of the string take effect.

ping/n 1 127.1 and ping/n 1 127.0.0.1 are equivalent.

I made two versions. Due to the 200-character limit for the signature, the other one couldn't be posted.

My requirements for this signature code are one is to try to have the shortest characters and the other is to try to be obscure and hard to read.

Try this under CMD, it's the same length as my current signature.

cls&(set,=何奈无──　。何奈可无是原，事奈无做人奈无&for,/l,%i,in,(22,-1,0)do,@call,set/p= %,:~%i,1%<nul&ping/n 1 127.1>nul)&set,=

My doubts have all been resolved. Thank you everyone!

And thanks to Brother Wunaike for providing the obscure and hard-to-read code ^_^ I discovered many usages that I didn't notice before

Originally posted by Wunaike at 2005-12-2 00:34:
Ping /n 1 127.1 and ping /n 1 127.0.0.1 are equivalent.

Re: Wunaike:

In that case, then you can refer to my discussion here about the latency effect of ping. The Oddity of Batch Programming – Mathematics (http://www.cn-dos.net/forum/viewthread.php?tid=8905#pid54227), see if it can explain the doubts I mentioned in it or correct the errors, and please reply to The Oddity of Batch Programming (http://www.cn-dos.net/forum/viewthread.php?tid=12388).

[ Last edited by willsort on 2005-12-2 at 12:45 ]

The batch processing of DOS has reached such a level, I really admire it.

(set t=abc)&echo %t%
The LZ is really funny. Of course it won't work like that. Don't forget there's a space after set. Of course this line won't run, only the following statements will. You can try the above one and you'll know. A bit careless when writing!

(set t=abc)&echo %t% doesn't work either. The effect is the same as set t=abc&echo %t%, both correctly display only when run the second time. Brother bagpipe, have you tested it?

[ Last edited by tianzizhi on 2006-11-6 at 03:22 AM ]

Delayed variable expansion effect

An expert is an expert

Reading the analysis by the masters is simply a pleasure!

set t=abc & call & echo %t%

Is this okay!

The upstairs is still not okay. You need to add the variable delay command in front.

@echo off&setlocal EnableDelayedExpansion
set t=abc&echo !t!
pause