Expect - Expecting while interacting

Question

I want to "listen" for a string outputted by the shell, while being in "interact" mode. Or i want to emulate interact mode somehow, that still allows me to listen for a specific string from the shell.

It seems interact only listens to the users input (the keys I press) and not what is returned by the shell.

How would I go about having Expect executing something everytime it sees a specific string, but otherwise let me use the shell interactively an unhindered?.

Example:

proc yay {} {
        send_user "Yay\n"
}

trap { # trap sigwinch and pass it to the child we spawned
  set rows [stty rows]
  set cols [stty columns]
  stty rows $rows columns $cols < $spawn_out(slave,name)
} WINCH

spawn bash

interact {
    interact -re "HOT" {
         yay
    }

    expect {
        fuzz yay
   }

}

If i run this and type "HOT" it responds with "Yay". As expected, it read my keys. But if i type

echo fuzz

The "expect" clause doesnt get triggered. Also "echo HOT" wont trigger anything either.

So is this possible or am I missing somthing. Perhaps I'd need to emulate interact in some kind of "expect, continue"-loop. Its just important that everything works normally in the shell..

Suggestions anyone?

Answer 1

You can use the expect_background command. From the man page:

takes the same arguments as expect, however it returns immediately. Patterns are tested whenever new input arrives.

You can modify your initial script like this:

#!/usr/bin/expect

proc yay {} {
 send_user "Yay\n"
}

trap { # trap sigwinch and pass it to the child we spawned
  set rows [stty rows]
  set cols [stty columns]
  stty rows $rows columns $cols < $spawn_out(slave,name)
} WINCH

spawn bash

expect_background {
 fuzz yay
}
interact -re "HOT" {
  yay
}