China DOS Union

What the person on the 5th floor said is very clear. Novices like us can understand it at a glance.

Well asked, well answered. Well added points, learned a lot...

The judgment about file extensions is very helpful for learning. Thanks a lot, senior!

Originally posted by 0401 at 2007-1-20 02:13 PM:
HoHo~ I'm more suitable for answering such basic questions

For question one, you can find out by doing it yourself.
The first sentence originally means to set variable a to empty, so there should be nothing on the right side of the equal sign...

0401 is a good teacher, very patient, worthy of our learning, but some students don't listen carefully in class. Hehe.

How to understand this code? There are many special symbol usages. Please ask everyone! Thank you in advance!
setlocal enabledelayedexpansion
for %%i in ("%tmp%\encrypt.tmp") do (
echo %%~zi >nul 2>nul
set size=%%~zi
set num=!size:~-1!
set /a mod=!num!%%2
if !mod! equ 0 (goto even) else (goto odd)
)

I also learned something, thanks for the explanation

Learned quite a lot of things~~~~

Originally posted by myth126 at 2007-4-1 09:11 PM:
How to understand the following code? There are many special symbols used. Please ask everyone! Thank you in advance!
setlocal enabledelayedexpansion
for %%i in ("%tmp%\encrypt.tmp") do (
echo %%~zi >nul 2&g ...

Hope experts can answer. I also don't understand. Probably the third line echo %%~zi >nul 2>nul I don't know what it means.

Originally posted by Vampire at 2007-4-17 06:48 PM:

Hope the experts can answer, I also have some doubts. Probably the third line echo %%~zi >nul 2>nul I don't know what it means.

Probably it means not to display the file size of %i, and also not to display errors.

Learned, I've learned some more things

Expand variable %%i to the file size. There is an explanation in for /?:

Variables with modifiers Description
%~I Expand %I with any quotes ("") around it removed.
%~fI Expand %I to the fully qualified pathname.
%~dI Expand %I to just the drive letter.
%~pI Expand %I to just the path.
%~nI Expand %I to just the file name.
%~xI Expand %I to just the file extension.
%~sI Expand the path to contain only the short name.
%~aI Expand %I to the file's file attributes.
%~tI Expand %I to the file's date and time.
%~zI Expand %I to the file size.
%~$PATH:I Search the directories listed in the PATH environment variable and expand %I to the first fully qualified name found. If the environment variable name is not defined or the file is not found during the search, this modifier expands to an empty string.

The following table lists modifier combinations that can be used to obtain composite results.

Variable (using combined modifiers) Description
%~dpI Expand %I to just the drive letter and path.
%~nxI Expand %I to just the file name and extension.
%~fsI Expand %I to the full pathname containing only the short name.
%~dp$PATH:I Search for %I in the directories listed in the PATH environment variable and expand to the drive letter and path of the first found result.
%~ftzaI Expand %I to an output line (like dir).

It is quite suitable for us beginners. But to be honest, there are some places I still don't understand what they mean. Alas! I can only take it slowly. Once again, I especially thank the GG on the first floor. You are really a very enthusiastic netizen. Your spirit is worthy of our learning.

Just had some understanding of the use of set just now in 5 minutes

Only when you understand the set command thoroughly can you write good things.