Re: [screen-users] automatically sending key to window

[Gerald Young]

On Monday 26 December 2011 1:30:10 am 蔡文博 wrote:
> Hello,
>
> I am using screen to run sipp (a SIP testing tool).
> Pressing "+" when sipp is running can increase call rate.
> I want to increase the call rate every 10 minutes.
> So I wonder if I can let screen to send a key to a window (which runs
> sipp) automatically after each interval.
>
> Appreciate if you can help, other solution is also welcome.
>
> Regards,
> Wenbo

Hello,

This is quite easy to do with Expect. Take for example the following script:
#!/usr/bin/expect -f 

set sending 0
set CTRLA \001
set CTRLZ \032

spawn sipp -sn uac 127.0.0.1
interact {
        timeout 1       { if {$sending} { send "+" } }
        $CTRLA          { set sending 1 }
        $CTRLZ          { set sending 0 }
}

When executed, Expect will internally spawn SIPp using the embedded UAC 
scenario. When Control+A is pressed, it will start sending a "+" to SIPp (ie. 
increasing call rate) every second. Pressing Control+Z stops the sending 
of "+" to SIPp. All other SIPp interactive commands work as usual.

You will probably want to edit the timeout value to 600 seconds (ie. 10 
minutes) and edit the sipp command line with your own parameters.

Regards,
Gerald Young