Set one variable in another batch file

Question

I would like to set a variable in another batch file, if it exsists. But it works only localy in the sub batch file. How can I fix this problem?

Main.bat:

SET TEMP=""
IF EXIST SUB.bat (
    CALL SUB.bat 
      REM Returns: TEMP="" IN MAIN
      ECHO %TEMP% IN MAIN
) ELSE (
      SET TEMP="DEFAULT VALUE"
)

Sub.bat:

SET TEMP="OTHER VALUE"
REM Returns: TEMP="OTHER VALUE" IN SUB
ECHO %TEMP% IN SUB

Output by calling Main.bat:

TEMP="OTHER VALUE" IN SUB
TEMP="" IN MAIN

Magoo · Accepted Answer · 2014-12-16 11:22:54Z

1

Two issues:

Your test is incorrect. Within a block statement (a parenthesised series of statements), the entire block is parsed and then executed. Any %var% within the block will be replaced by that variable's value at the time the block is parsed - before the block is executed - the same thing applies to a FOR ... DO (block).

Hence, IF (something) else (somethingelse) will be executed using the values of %variables% at the time the IF is encountered.

Try using CALL ECHO %%TEMP%% to display the altered value and look up "delayedexpansion" for endless SO items on this frequently-encountered subject.

Second issue - which impinges on the first.

TEMP and TMP are special variablenames which specify the location of a temporary-files directory. Best not to change them as unexpected results may ensue. Use another variablename.

answered Dec 16, 2014 at 11:22

Magoo

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3 Comments

user2722077 Over a year ago

But the variable is empty, if I use it in another Batch file, which has been called by the Main.bat. Why?

Magoo Over a year ago

Without the exact code you are using, any response would be a guess unfortunately.

user2722077 Over a year ago

I don't know what I did or if I did anything but it works now -.- THX!

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