Running a bash shell script in java

Question

I want to run a shell script from my program below but it doesn\'t seem to do anything. I\'ve run the same command directly in the linux terminal and it works fine so I\'m g

Answer 1

When you execute a script from Java it spawns a new shell where the PATH environment variable is not set.

Setting the PATH env variable using the below code should run your script.

String[] env = {"PATH=/bin:/usr/bin/"};
String cmd = "you complete shell command";  //e.g test.sh -dparam1 -oout.txt
Process process = Runtime.getRuntime().exec(cmd, env);

Answer 2

Try this, it will work.

String[] cmd = new String[]{"/bin/sh", "path/to/script.sh"};
Process pr = Runtime.getRuntime().exec(cmd);

Answer 3

You should use the returned Process to get the result.

Runtime#exec executes the command as a separate process and returns an object of type Process. You should call Process#waitFor so that your program waits until the new process finishes. Then, you can invoke Process.html#getOutputStream() on the returned Process object to inspect the output of the executed command.

An alternative way of creating a process is to use ProcessBuilder.

Process p = new ProcessBuilder("myCommand", "myArg").start();

With a ProcessBuilder, you list the arguments of the command as separate arguments.

See Difference between ProcessBuilder and Runtime.exec() and ProcessBuilder vs Runtime.exec() to learn more about the differences between Runtime#exec and ProcessBuilder#start.