How do I run execute commands from a file?

Question

How do I execute commands by running a file in Linux? I need to run the following commands:

cd /bin
java -cp main

What should the file extension be?

It could be any extension but the convention (in bash) is to use `.sh` (and make the file executable, of course...) — Nir Alfasi, Mar 22 '15 at 03:56
Use `ProcessBuilder`, it will allow you to define the execution context (directory) from which the command should be executed, for [example](http://stackoverflow.com/questions/28955020/compiling-and-executing-using-exec-in-java-fails-using-command-that-works-from-t/28955036#28955036) and [example](http://stackoverflow.com/questions/15218892/running-a-java-program-from-another-java-program/15220419#15220419) — MadProgrammer, Mar 22 '15 at 03:58

score 2 · Accepted Answer · edited Jun 20 '20 at 09:12

2

Welcome to bash scripting.

What you want to achieve, is one of the most important features of any terminal, to execute commands from a file.

In Linux, you need not have any particular extension for a bash file, although the .sh extension is customary.

Create a file with any name, (I'll choose script.sh)

The contents:

#!/bin/bash
cd /bin
java -cp main

Make it executable now:

$ chmod a+x script.sh

Now execute the script:

$ ./script.sh

Voila! Your first bash script. You can learn more about bash scripting here.

Since the OP is running Raspian Wheezy, this can help him create scripts.

edited Jun 20 '20 at 09:12

Community

answered Mar 22 '15 at 04:00

shauryachats

When I try to execute it I get "bash: ./start.sh: Permission denied." – Lucas Rufkahr Mar 22 '15 at 04:28
Did you do `chmod a+x start.sh`? – shauryachats Mar 22 '15 at 04:30
Yes. It just won't let me execute it. – Lucas Rufkahr Mar 22 '15 at 04:34
Which distro are you running? – shauryachats Mar 22 '15 at 04:36
Raspian "Wheezy" www.raspberrypi.org – Lucas Rufkahr Mar 22 '15 at 04:37
Try `sudo chmod 755 start.sh`. – shauryachats Mar 22 '15 at 04:40

score 0 · Answer 2 · edited May 23 '17 at 12:12

Doing this is possible with java.

Runtime.exec() method should work for you.

Write a shell script file and invoke it from the java code like this...

{
   Process pro = Runtime.getRuntime().exec("./script.sh");                        
   pro.waitFor();
}

The script that you create contains your desired command by following the bash introduction given in the other answer.