Run java from shellscript

xlinuks · 12-10-2006, 03:37 PM

Hello,
I have a little Java program that is supposed to be run with a custom amount of memory, to do this I need to create a shell script (I've created a .bat script for windows with no problem). BUT, under Linux my script runs correctly only from the command line - I need to run it at double click as well. The script is supposed to launch a .jar (Java executable) file that's in the same directory. Here's my script (called "start_java"):

Code:

#! /bin/sh
#cd $PWD
java -Xms64m -Xmx256m -jar ./MyApplication.jar

It runs successfully from the command line like "./start_java" & Enter.
At double click it wont launch - I think it's about specifying the directory where Java should find the "MyApplication.jar" - here is my problem since I don't know how to do it. From the command line we say "./" to specify the current dir, but using the double click method - the application (java) thinks probably that the current folder is the directory where it is installed.
Hope you got me correctly (the CD $PWD didn't work either).
Please help!

Brian1 · 12-10-2006, 04:35 PM

First there is no space in the first line. It is one single word as one might say.
#!/bin/bash

The cd $PWD is actually what? You need to define the string variable $PWD

Brian

xlinuks · 12-10-2006, 04:59 PM

Thanks for the hint. I realized whats the matter: when using double click the "PWD" variable points to my home dir, instead of the directory from where the shell script has been launched - and I have no clue how to fix this.

Code:

#!/bin/bash
nowdir=$PWD
echo $nowdir >> /home/brian/Desktop/thefile.txt
java -Xms64m -Xmx256m -jar $nowdir/MyApplication.jar

-from the command line I get a file (thefile.txt) on the desktop containing "/home/brian/Desktop"
-by double clicking the shellscript (from the Desktop as well) I get same file with only "/home/brian"
So, my problem is: How to let the shellscript correctly identify the folder it has been launched from?

Brian1 · 12-10-2006, 05:07 PM

Is the same file being overwritten?
First run it like you say, then delete the thefile.txt and run it again where you want the second time. If it is correct then the second attempt is not forcing and overwrite.

Brian

xlinuks · 12-10-2006, 06:38 PM

I create the "thefile.txt" from the shell script just to prove that the shellscript behaves differently when it is being launched by double-click or from the command line - both cases have different understanding about the 'current directory' - which is why I can't run the "MyApplication.jar" file double-clicking the launcher ( the "start_java" file ).
Thanks for your time.

Electro · 12-10-2006, 07:46 PM

I have the same problem, but I do not rely on desktop icons. State the the PATH environment variable or use the full path to the program.

The reason why the script is behaving strangly. All programs that are loaded gets their own seperate environment because Linux is a multi-tasking and a virtual memory OS. To get the script run in the same environment, you type ". [script name]". The dot says in this environment, run this script.

In your script, I suggest adding . on the same line that reads java before java. This will make it easier for Linux to run the program in the same environment as the script is run.

xlinuks · 12-11-2006, 02:53 PM

Putting the point before 'java' didn't help either

Brian1 · 12-11-2006, 03:06 PM

Not a very good script writer so out of ideas.

Brian

Electro · 12-11-2006, 03:50 PM

Assuming MyApplication.jar is in $HOME/bin/javaprog

Code:

#!/bin/sh
#PATH="/bin:/sbin:/usr/bin:/usr/sbin"
PROGRAM_PATH="$HOME/bin/javaprog"
cd "$PROGRAM_PATH"
java -Xms64m -Xmx256m -jar MyApplication.jar
unset PROGRAM_PATH

Please read my previous post thoroughly.

xlinuks · 12-12-2006, 02:36 AM

That's the problem,that there's no way to know where the end user might unzip the application.