Batch and the for loop

Question

Hi everyone,

I have a java application launched by a .cmd file. I want to set the classpath of the application through this batch, all the needed jars are into a lib folder.

Here is what I tried :

 set _classpath=.
for %%i in (%1/lib/*.*) do ( set _classpath=%_classpath%;%%i )

Surprisingly, it seems that it does not act as expected. Let's say there is 3 jar in the lib folder :

• pikachu.jar
• sonic.jar
• mario.jar

Here is what happens :

1. set _classpath=.
2. set _classpath=.;pikachu.jar
3. set _classpath=.;sonic.jar
4. set _classpath=.;mario.jar

Obviously, what I am looking to get is

• set _classpath=.;pikachu.jar;sonic.jar;mario.jar

Any idea ?

Thanks and regards,

Answer 1

CMD.EXE is expanding the %...% before running the loop.

You need delayed variable expansion, this is explained in set /? from a command prompt.

Answer 2

Place this at the top of your batch file:

setlocal enabledelayedexpansion

Then inside the for loop, replace %_classpath% with !_classpath!

Without delayed expansion enabled, %_classpath% gets expanded once, at the beginning of your for loop.

---

[Edit] In response to a comment, here is a full code-listing

@echo off
setlocal enabledelayedexpansion

set _classpath=.
for %%i in (%1/lib/*.*) do (
    set _classpath=!_classpath!;%%i
)

echo %_classpath%
pause