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To start two telnets

Posted by sharmila (sharmila), 24 September 2005
How to start two telnet processes from a single expect script?

Posted by admin (Graham Ellis), 24 September 2005
You can run two spawn commands ...

OK - It's not quite that simple if you want both telnet sessions to be concurrent rather than run one after the other. If you want them to be concurrent, you need to tell your subsequent send and expect commands which of the spawned telnet processes you wish to sned to, and which (or perhaps both) you want to wait on when you do an expect.

When you spawn a process, a valiable called spawn_id is set by expect, and subsequent send and expect commands will use that variable.   If you spawn a second process, then that variable is overwritten ... so you must save it first to retain full access to the first process.

spawn  process1
set firstspawn $spawn_id
spawn  process2
set secondspawn $spawn_id

you can then send and expect to and from each individual process by resetting spawn_id before you send or expect.  For example, if you want to wait for the password prompt on the first preocess and send abc123 back, you could write:

set spawn_id $firstspawn
expect "sword: "
send "abc123\r"

If you want to expect from multiple processes at the same time, you can do so using the -i option to expect and give it a list of processes; you'll then handle the first match from any of the spawned processes in the list.   There are complete working examples of this in our expect processes resources area



Posted by sharmila (sharmila), 7 October 2005
Thanks



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