China DOS Union

The following is the translation:

Regarding the part where delims= in the content, if it is delims=\" I know that \ is used as the delimiter, but what does it mean when there is nothing behind it? I can't figure it out. Hope an expert can explain. Also, please explain the red parts for me? Please.
@echo off&setlocal EnableDelayedExpansion
set a=1
for /f "delims=%%i in ('dir /a-d/b/s *.txt') do (
if not "%%~ni"=="%~n0"
!%%~xi"
set/a a+=1
)

Explanation of red parts:
- "delims=": In the for /f command, delims is used to specify the delimiter. When delims is set to an empty value, it means using the default delimiters, which are spaces, tabs, etc.
- "if not "%%~ni"=="%~n0"": It is an if condition judgment. %%~ni is the name of the current loop variable i, and %~n0 is the name of the current batch file without the extension. It is judging whether the name of the current loop variable i is not equal to the name of the current batch file without the extension.
- "%%~ni!a!%%~xi": %%~ni is the name of the current loop variable i without the extension,!a! is the value of variable a, %%~xi is the extension of the current loop variable i. So it is renaming the file to the name without extension + value of variable a + extension.

lxmxn
Thank you in advance for your answer,
If that's the case then I might as well not write it, right? Like the following content, is there anything wrong with it?
I tried it, the program runs normally, just don't know if it will have problems in some other environment.
Also, for the red part, why use only a single % sign?
@echo off&setlocal EnableDelayedExpansion
set a=1
for /f %%i in ('dir /a-d/b/s *.txt') do (
if not "%%~ni"=="%~n0" (
ren "%%i" "%%~ni!a!%%~xi"
set/a a+=1
)
)

In the for /f statement, by default, spaces or tabs (that is, the character produced by pressing the tab key which is 8 spaces) are used as delimiters. If the value of delims is not specified, it means that spaces or tabs are used as delimiters.

I sort of understand, but not completely. I'll learn it step by step.

Go to see the example here
http://www.cn-dos.net/forum/viewthread.php?tid=46126&fpage=2
"delims="
The content of the text file is divided into several segments by each line by for. The symbol for segmenting is called a delimiter, and the system default is a space.
delims means define limite to define the boundary. "delims= " means that the delimiter is a space symbol to divide each line into several segments. This is the system default, and at this time, you can not have delims=space, which is also the same. If this sentence is changed to delims=k, each line will be divided into several segments according to the letter k. for by default only captures the first segment of each line into memory for operation.
For example, the content of *.txt is
11 12 13
21 22 23
31 32 33
Then what for captures is
11
21
31
Special note: This for will not capture the entire line of data. It will only capture the first segment of each line! If you want for to capture the entire line of data, you have to add a disruptor, that is, tokens=*
”%%~ni“
Here n comes from the English name, which means name. The ~ symbol represents removing the double quotes. So "%%~ni" means to expand the file name read by parameter %%i. How to expand? For example, if %%i represents the file name 123456.txt, then %%~ni represents: 123456
And %%~xi represents:.txt (x is the meaning of extended)
if not "%%~ni"=="%~n0" is: if the file name obtained from %%~ni from %i is not equal to the file name obtained from %~n0 from %0 (without extension), then what.

[ Last edited by 5yue5 on 2009-2-15 at 22:56 ]