How to Retrieve the Exit Code of a Bash Command in Java

How can I obtain the exit code from a bash command executed in my Java application?

Process process = Runtime.getRuntime().exec("bash -c 'your_command'");
process.waitFor();
int exitCode = process.exitValue();

When executing system commands from within Java, it's often necessary to handle the exit codes to determine if the command executed successfully or if there were any errors. This guide outlines how to run a bash command in Java and retrieve its exit code effectively.

try {
    ProcessBuilder processBuilder = new ProcessBuilder("bash", "-c", "your_command");
    Process process = processBuilder.start();
    int exitCode = process.waitFor();
    System.out.println("Exit Code: " + exitCode);
} catch (IOException | InterruptedException e) {
    e.printStackTrace();
}

Causes

• Command may not exist or is incorrectly specified.
• Permissions issues preventing command execution.
• The command fails to execute for other reasons, such as incorrect syntax.

Solutions

• Use the ProcessBuilder class for better control and handling of input/output streams.
• Ensure the command is correctly formatted and verify paths for executables.
• Check for errors in the execution process by reading the error stream.

Mistake: Not waiting for the process to finish before retrieving exit code.

Solution: Use process.waitFor() to ensure the command finishes executing.

Mistake: Ignoring error streams which may contain useful debugging information.

Solution: Read the error stream of the process if the exit code indicates failure.