splicer/jbang/Splicer.java

///usr/bin/env jbang "$0" "$@" ; exit $?

//DEPS com.fasterxml.jackson.core:jackson-databind:2.18.4
//DEPS org.apache.commons:commons-exec:1.5.0

import java.io.ByteArrayOutputStream;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.stream.Collectors;

import org.apache.commons.exec.CommandLine;
import org.apache.commons.exec.DefaultExecutor;
import org.apache.commons.exec.PumpStreamHandler;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;

public class Splicer {

	private static final Logger logger = Logger.getLogger(Splicer.class.getName());

	public static void main(String[] args) throws InterruptedException, JsonProcessingException {
		
		if (args.length == 0) {
			System.out.println("This program allows you to run several commands at the same time."
					+ "\n\nUsage: Splicer.java cmd1 cmd2 cmd3 ..."
					+ "\n\nExample: ./Splicer.java \"ls -l\" \"df -kh\"\n");
			return;
		}
		
		ExecutorService executorService = Executors.newFixedThreadPool(args.length);

		List<Callable<ExecutionResult>> callables = List.of(args).stream()
				.map(command -> new Callable<ExecutionResult>() {
					@Override
					public ExecutionResult call() throws Exception {
						return executeShell(command);
					}
				}).collect(Collectors.toList());

		List<ExecutionResult> results = executorService.invokeAll(callables).parallelStream().map(f -> {
			try {
				return f.get();
			} catch (InterruptedException | ExecutionException e) {
				logger.log(Level.SEVERE, "Error found!", e);
			}
			return null;
		}).filter(Objects::nonNull).collect(Collectors.toList());

		executorService.shutdown();
		
		System.out.println(new ObjectMapper().writeValueAsString(Map.of("results", results)));
	}

	public static ExecutionResult executeShell(String command) {
		ByteArrayOutputStream tempOut = new ByteArrayOutputStream();
		try {
			CommandLine cmdLine = CommandLine.parse(command.trim());
			DefaultExecutor executor = DefaultExecutor.builder().get();
			PumpStreamHandler streamHandler = new PumpStreamHandler(tempOut);
			executor.setStreamHandler(streamHandler);
			int exitValue = executor.execute(cmdLine);
			return new ExecutionResult(command, exitValue, new String(tempOut.toByteArray()));
		} catch (Exception e) {
			logger.log(Level.SEVERE, "Execute cmd failed: " + command.trim(), e);
		}
		return new ExecutionResult(command, -1, new String(tempOut.toByteArray()));
	}
	
	public static record ExecutionResult(String command, Integer exitValue, String output) {
		
	}
}