Question 1

How do I capture output from a child process using Childprocess?

Accepted Answer

Redirect stdout to a file or pipe, as shown in the README examples—e.g., set process.io.stdout to a Tempfile or use IO.pipe for real-time reading. However, for one-off commands, Ruby's backticks might be simpler.

Question 2

Childprocess vs Ruby's Process.spawn: which is better?

Accepted Answer

Childprocess builds on Process.spawn, adding a higher-level API with convenience methods for I/O, waiting, and termination. Use Childprocess for enhanced control and cross-platform consistency; Process.spawn suffices for low-level, minimal abstraction.

Question 3

Why does my Childprocess command fail on JRuby with PATH issues?

Accepted Answer

This is due to JRuby's limitations with environment variables. Set Childprocess.posix_spawn = true to mitigate PATH errors, or configure JAVA_OPTS for Java >=9 as per the caveats in the README.

Question 4

How to kill a child process and all its subprocesses?

Accepted Answer

Set process.leader = true before starting to create a new process group, ensuring the entire tree dies when terminated, as explained in the 'Ensure entire process tree dies' section.

Question 5

Can Childprocess handle interactive commands that need stdin?

Accepted Answer

Yes, by setting process.duplex = true, which makes process.io.stdin available after start for writing input, as demonstrated in the 'Write to stdin' example.

Question 6

What are the performance implications of using Childprocess?

Accepted Answer

Overhead is minimal as it wraps Ruby's Process.spawn, but for high-frequency spawning, direct system calls might be faster. Childprocess prioritizes reliability and portability over raw speed.

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