Function spawn_bash 

pub fn spawn_bash(timeout: Option<u64>) -> Result<PtyReplSession, Error>

Spawn bash in a pty session, run programs and expect output

The difference to spawn and spawn_command is:

• spawn_bash starts bash with a custom rcfile which guarantees a certain prompt
• the PtyBashSession also provides wait_for_prompt and execute

timeout: the duration until which exp_* returns a timeout error, or None additionally, when dropping the bash prompt while bash is still blocked by a program (e.g. sleep 9999) then the timeout is used as a timeout before a kill -9 is issued at the bash command. Use a timeout whenever possible because it makes debugging a lot easier (otherwise the program just hangs and you don’t know where)

bash is started with echo off. That means you don’t need to “read back” what you wrote to bash. But what you need to do is a wait_for_prompt after a process finished.

Also: if you start a program you should use execute and not send_line.

For an example see the README

Examples found in repository

examples/bash.rs (line 5)

fn main() -> Result<(), Error> {
    let mut p = spawn_bash(Some(1000))?;
    p.execute("ping 8.8.8.8", "bytes")?;
    p.send_control('z')?;
    p.wait_for_prompt()?;
    // bash writes 'ping 8.8.8.8' to stdout again to state which job was put into background
    p.execute("bg", "ping 8.8.8.8")?;
    p.wait_for_prompt()?;
    p.send_line("sleep 0.5")?;
    p.wait_for_prompt()?;
    // bash writes 'ping 8.8.8.8' to stdout again to state which job was put into foreground
    p.execute("fg", "ping 8.8.8.8")?;
    p.send_control('c')?;
    p.exp_string("packet loss")?;
    Ok(())
}

examples/bash_read.rs (line 5)

fn main() -> Result<(), Error> {
    let mut p = spawn_bash(Some(2000))?;

    // case 1: wait until program is done
    p.send_line("hostname")?;
    let hostname = p.read_line()?;
    p.wait_for_prompt()?; // go sure `hostname` is really done
    println!("Current hostname: {hostname}");

    // case 2: wait until done, only extract a few infos
    p.send_line("wc /etc/passwd")?;
    // `exp_regex` returns both string-before-match and match itself, discard first
    let (_, lines) = p.exp_regex("[0-9]+")?;
    let (_, words) = p.exp_regex("[0-9]+")?;
    let (_, bytes) = p.exp_regex("[0-9]+")?;
    p.wait_for_prompt()?; // go sure `wc` is really done
    println!("/etc/passwd has {lines} lines, {words} words, {bytes} chars");

    // case 3: read while program is still executing
    p.execute("ping 8.8.8.8", "bytes of data")?; // returns when it sees "bytes of data" in output
    for _ in 0..5 {
        // times out if one ping takes longer than 2s
        let (_, duration) = p.exp_regex("[0-9. ]+ ms")?;
        println!("Roundtrip time: {duration}");
    }
    p.send_control('c')?;
    Ok(())
}