Example: Executing a shell script from java

Question

Hi. There are many other posts in the forums related to executing a unix script from java, but I wanted to post another example that I thought might be helpful...
The key thing to executing the script is to include the -c switch for the sh command. This tells the sh command that you are passing a string to be interpreted as input. Without this switch, the script does not execute as you'd expect it to. Also, use a string array to pass each part of the sh command.
Here is a working sample class, along with a test script to execute it:
public class TestShellScript {
public static void main(String[] args)
String[] chmod = {"chmod","777","testscript1"};
String[] runscript = {"sh","-c","./testscript1 > jdata.out"};
Runtime rtime = Runtime.getRuntime();
try
rtime.exec(chmod); // Set the authorities for testing
rtime.exec(runscript); // Run the script with redirection
catch (IOException e)
e.printStackTrace();
rtime = null;
Here is a test script to wrap the java call:
#!/bin/sh
cd /<your script dir>
export -s CLASSPATH=/<your jar dir>/TestShellScript.jar
export -s PATH=/<your script dir>:/usr/bin
java TestShellScript
- Hope this helps.

Answer 1

I don't know exactly but the code written below is working fine try the same with your code .Even with your code instead running the code with
" ./<filename> ",if you execute it with "sh <filename>" command without changing the mode of the file it is executing properly.
import java.io.*;
import java.util.*;
public class ScriptBuilder
public ScriptBuilder()
public void writeScript() throws java.io.IOException
FileWriter writer = new FileWriter(new File("test_script"));
writer.write("#! /bin/sh\n");
writer.write("ll>/home/faiyaz/javaprac/checkll");
writer.flush();
writer.close();
Runtime rt= Runtime.getRuntime();
rt.exec("chmod 777 test_script");
rt.exec("./test_script");
} public static void main (String[] args)throws java.io.IOException
ScriptBuilder sb = new ScriptBuilder();
sb.writeScript();
}