Question

I am making a console Java app where you can type in console commands like Terminal on Macintosh/Ubuntu/Windows Command Prompt and then it outputs it to a log.

I was wondering, when executing a system/console command, how I get the results/log from that command?

Note: I mean literal code + explanation please.

Answer 1

There are a number of ways to do this, the easiest is this (or a variant), from this example.

Process child = Runtime.getRuntime().exec(command);
InputStream in = child.getInputStream();

If you have internal commands you’d like to go to two places, consider something like a Commons IO TeeOutputStream.

You could combine the above techniques to get all output, whether from internal or external commands, to both your console, and a “shadow” log file.