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Re: Backgrounding interactive processes

by hbo (Monk)
on Jul 25, 2004 at 22:50 UTC ( #377315=note: print w/ replies, xml ) Need Help??

in reply to Backgrounding interactive processes

Assuming the VPN startup uses stdin/stdout, you can use the Expect module to converse with it. To background it, you can send it the STOP signal: kill $SIG{STOP}, $pid; To have it continue send the CONT signal: kill $SIG{CONT},$pid;. You can get the pid from the spawn method of expect. Or, you could issue the ^Z/bg commands via Expect, which sounds simpler, on reflection.

As to knowing whether it has succeeded or not, you probably need to come up with a test based on the ability to connect to a VPN protected resource, like the DNS servers for instance.

Update: Doing job control with Expect will only work if the command you spawn is a shell with job control, and not the VPN command itself. So you would spawn the shell, and then exec the VPN command with a send to the shell. It may not be simpler to do this compared to spawning the VPN command itself.

"Even if you are on the right track, you'll get run over if you just sit there." - Will Rogers

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