[add information about expect's spawn command, pointers to its man page on http://www.tcl.tk/man/ , etc.]
spawn creates a session with a program or remote device that Expect can manage. Spawned sessions can be automated using other Expect commands, such as expect, interact and exp_send.
The man page for spawn is actually part of the Expect man page http://www.tcl.tk/man/expect5.31/expect.1.html .
A very simple example - ping an ip address:
#!/bin/sh
# The next line is executed by /bin/sh, but not tcl \
exec /homes/ashnoc01/noc/rbacon/tcl/ActiveTcl/bin/tclsh8.4 $0 ${1+"$@"}
package require Expect
spawn -noecho /usr/local/bin/nping -c 5 $argv
log_user 0
expect {
"\r" {
puts -nonewline "$expect_out(buffer)"
exp_continue
}
eof {
puts -nonewline "$expect_out(buffer)"
}
}
puts "AutoPing finished\n"
exitOutput:
> AutoPing 62.188.74.130
PING 62.188.74.130: 64 data bytes
EchoReply from 62.188.74.130: len=64 ttl=242 seq=0 time=81.157 ms.
EchoReply from 62.188.74.130: len=64 ttl=242 seq=1 time=80.768 ms.
EchoReply from 62.188.74.130: len=64 ttl=242 seq=2 time=80.709 ms.
EchoReply from 62.188.74.130: len=64 ttl=242 seq=3 time=80.915 ms.
EchoReply from 62.188.74.130: len=64 ttl=242 seq=4 time=80.940 ms.
----62.188.74.130 PING Statistics----
5 transmitted, 5 received, 0.00% packet loss.
round-trip (ms) min/avg/max = 80.709/80.898/81.157
var/sdev/skew/kurt = 0.030/0.174/0.323/1.311
AutoPing finished