Percent Signs Stripped from Batch File Text(batch中需要两个%)

http://forum.sysinternals.com/batch-file-problems-with-xp_topic13569.html

I am trying to convert a batch file script I wrote for Windows 98SE to run under XP however I've encountered a really annoying problem and not entirely sure how to fix it.

My script starts by drag and dropping a file to the shortcut (the batch file) on my desktop.
The batch file then evaluates %1 if null it runs notepad to edit itself otherwise it continues to run the rest of commands.
The code seems to fail under XP if the filename + path passed to %1 contains spaces but not under 98SE since it generates short file names with drag and drop.

To illustrate the problem I wrote a simple batch file called test.bat


@echo off
if "%1" == "" goto null
echo.
echo found this - %1
goto end

:null
echo.
echo nothing was passed
goto end

:end

Running test.bat

>test.bat
nothing was passed

>test.bat test
found this - test

>test.bat test "C:\Documents and Settings\User\Desktop\procexp.exe"
and was unexpected at this time.

"and was unexpected at this time." - and what is that supposed to mean??

Any suggestions??

Richard S.

molotov

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Quote molotov

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  Quote  Reply Posted: 07 February 2008 at 2:50pm

Hi Richard,

 

Try:

test.bat "hamster chicken goat"

 

You'll get "chicken was unexpected at this time".

 

Try changing it to:

if "%%1" == "" goto null

(add an extra '%').

Edited by molotov - 07 February 2008 at 2:52pm

Daily affirmation:
net helpmsg 4006

＝＝＝＝＝＝＝

http://support.microsoft.com/kb/75634

Percent Signs Stripped from Batch File Text

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SUMMARY

Using a percent sign (%) in a batch file requires that two percent signs (%%) be...

Using a percent sign (%) in a batch file requires that two percent signs (%%) be specified.

For example, the command to display "5%" from a batch file would be :

   ECHO 5%%

MORE INFORMATION

MS-DOS uses %1, %2, ... %9 as replaceable command line parameters. For example,...

MS-DOS uses %1, %2, ... %9 as replaceable command line parameters. For example, before executing the command ECHO %1, %1 will be replaced with the first parameter passed to the batch file. %0 is replaced with the command used to execute the batch file.

A single percent sign on a line is treated as a "nul" character in a batch file. For example:

   ECHO %     is processed as ECHO   ECHO a%b   is processed as ECHO ab

If a command contains two percent signs, MS-DOS will treat any characters between them as an environment variable to be expanded. For example, if the SET command shows that the current environment variables are

   COMSPEC=C:\COMMAND.COM   PATH=C:\DOS   PROMPT=$P$G   B=C

then

   ECHO %PATH%     is processed as ECHO C:\DOS   ECHO a%b%       is processed as ECHO aC   ECHO a%b b%a    is processed as ECHO aa

If there are no characters between the two percent signs, one percent sign is stripped off and the other will remain. This is why a FOR command that echos the name of each file with a .COM extension would be

   FOR %V IN (*.COM) DO ECHO %V

but if the same command is placed in a batch file, the following is required:

   FOR %%V IN (*.COM) DO ECHO %%V

Reference(s):

"Microsoft MS-DOS Batch File Quick Reference," Microsoft Press.

---

APPLIES TO

• Microsoft MS-DOS 3.1
• Microsoft MS-DOS 3.2 Standard Edition
• Microsoft MS-DOS 3.21 Standard Edition
• Microsoft MS-DOS 3.3 Standard Edition
• Microsoft MS-DOS 3.3a
• Microsoft MS-DOS 4.0 Standard Edition
• Microsoft MS-DOS 4.01 Standard Edition
• Microsoft MS-DOS 5.0 Standard Edition
• Microsoft MS-DOS 5.0a
• Microsoft MS-DOS 6.0 Standard Edition
• Microsoft MS-DOS 6.2 Standard Edition
• Microsoft MS-DOS 6.21 Standard Edition
• Microsoft MS-DOS 6.22 Standard Edition

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KB75634

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This article was written about products for which Microsoft no longer offers support. Therefore, this article is offered "as is" and will no longer be updated.

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