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Command execution doesn’t use SSH or the network. There’s a dedicated channel between the host and a guest agent running inside the VM, completely separate from the sandbox’s network stack. The agent spawns processes, streams output back, and reports exit codes. One nice consequence: exec works even when a sandbox has networking fully disabled.

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Execute a command

Run a command and wait for it to complete. You get back the exit code, stdout, and stderr. 
let output = sb.exec("python", ["-c", "print('hello')"]).await?;
println!("{}", output.stdout()?);     // "hello\n"
println!("{}", output.status().code); // 0

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Execution options

These options apply to a single execution and don’t change the sandbox’s defaults. 
let output = sb.exec("python", |e| e
    .args(["compute.py"])
    .cwd("/app")
    .env("PYTHONPATH", "/app/lib")
    .timeout(Duration::from_secs(30))
    .rlimit(RlimitResource::Nofile, 1024)
).await?;

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Shell commands

Run a command through the sandbox’s configured shell (defaults to /bin/sh). Useful for pipelines, redirects, and other shell syntax that exec doesn’t interpret. 
let output = sb.shell("ls -la /app && echo done").await?;

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Stream output

For long-running processes or large output, streaming gives you stdout, stderr, and exit events as they happen instead of buffering everything until the command finishes. 
let mut handle = sb.exec_stream("tail", ["-f", "/var/log/app.log"]).await?;

while let Some(event) = handle.recv().await {
    match event {
        ExecEvent::Stdout(data) => print!("{}", String::from_utf8_lossy(&data)),
        ExecEvent::Stderr(data) => eprint!("{}", String::from_utf8_lossy(&data)),
        ExecEvent::Exited { code } => break,
        _ => {}
    }
}

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Interactive attach

Bridges your terminal directly to a process inside the sandbox for a fully interactive PTY session. Useful for debugging, running REPLs, or anything that expects a real terminal. 
let exit_code = sb.attach_shell().await?;

let exit_code = sb.attach("python", |a| a
    .env("DEBUG", "1")
    .cwd("/app")
    .detach_keys("ctrl-q")
).await?;
Press Ctrl+] (or your configured detach keys) to detach from the session without stopping the process. The process keeps running inside the VM and you can reattach later via its session ID.

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Write stdin

Streaming handles can also accept stdin. Enable stdin_pipe and write bytes to it. Combined with tty: true, this lets you drive interactive processes programmatically. 
let mut handle = sb.exec_stream("python", |e| e.stdin_pipe().tty(true)).await?;
let stdin = handle.take_stdin().unwrap();
stdin.write(b"print('hello')\n").await?;
stdin.write(b"exit()\n").await?;
handle.wait().await?;