There is a difference in the behaviour of KornShell and Bash you might want to observe: bashs child processes put in background won't be terminated once the process controlling that terminal dies. KornShell processes will, however, die with their parents until they are started with the "nohup" (no hangup [upon loss of terminal]) command.

To explain that in more common terms: when you issue 'ssh -f host "cmd"' you basically open an interactive session like you would log on, issue "cmd" in this session and then close it again. The whole procedure will normally wait until "cmd" is finished. By logging on, you create a (pseudo-)terminal, which will be closed when you log off.

Now consider a background process as "cmd". It is not possible to wait until it finished, because that could possibly be forever. In fact you just want to *start* it, not waiting for its end. So you start a (in fact interactive) shell, start in this shell a process in background and then want to terminate the shell - the child will, if this shell is a KornShell - die with the parent.

What you could do in this case is:

- start the job in background
- find out its PID (inside the process environment)
- issue a "nohup -p PID"
- terminate the controlling shell - the nohup-ped process will survive

"cmd" in this case would look like (i will use vmstat as an example):

Code:

vmstat 10 > logfile & ; PID="$(jobs -l | sed -n 's/^\[[0-9]*\]  *+  *\([0-9]*\) .*$/\1/p') ; nohup -p $PID

The output of "jobs" will decorate the last recently issued background job with a "+", which means, this is the job which will become the foreground job when the command "fg" is issued. The sed-statement just extracts the PID from this line.

HTH

bakunin