Question

I read the following code, but I do not understand how it works:

set accum ""
set timeout 1
    expect {
        -re {.+} {
            set accum "${accum}$expect_out(0,string)" 
            exp_continue
        }
    }
set timeout 10

at the beginning, we set accum and timeout, then there is a expect command try to match something? and after it, we set the timeout as 10, how the whole code works? and does this mean?

Answer 1

Until the code times out (1 second after the last match of anything), any time it matches something (which is any sequence of characters — possibly excluding newline — because of -re {.+}) it appends it to the accum variable and restarts expecting something (the exp_continue is indeed magic).

It would be more efficient to use append accum $expect_out(0,string), but the way it is done isn’t wrong.