Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!zaphod.mps.ohio-state.edu!julius.cs.uiuc.edu!psuvax1!rutgers!njin!princeton!dae!pfalstad From: pfalstad@dae.Princeton.EDU (Paul John Falstad) Newsgroups: comp.unix.questions Subject: Re: Preventing Idle in telnet, security, and bg. Message-ID: <2911@idunno.Princeton.EDU> Date: 28 Sep 90 17:07:53 GMT References: <14228@hydra.gatech.EDU> <2903@idunno.Princeton.EDU> Sender: news@idunno.Princeton.EDU Distribution: comp Organization: Princeton University, Princeton, New Jersey Lines: 22 In article <2903@idunno.Princeton.EDU> pfalstad@bow.Princeton.EDU (Paul John Falstad) writes: >Try this in your favorite shell: > >$ csh (or whatever) >% sleep 100 & >% kill -HUP $$ >$ ps Well that was dumb of me. Of course this works in any shell, but it doesn't prove anything. The tty driver sends SIGHUP to all processes in the process group associated with the terminal when you logout. So if your login shell is sh, all your &'d processes will get killed when you logout because sh doesn't create a new process group for its children. All children of the shell have the same process group of the shell. csh creates new process groups for all the children it spawns, so they will not get the SIGHUP when the tty is closed. Sorry. -- <- Pnews isn't printing this line. Anyone know why? Here is the address to complain to: pfalstad@phoenix.princeton.edu PLink:HYPNOS GEnie:P.FALSTAD CIS: 70016,1355 That address again, sync@thumper.princeton.edu PLink:OHS738 GEnie:OHS738 CIS: 4128 143 1234 937