CentOS - Jan 2008 - centos command to monitor a process for exit

Is there a command that will monitor a process for exiting (crash or 
normal exit) and
then execute another command based on the said process no longer being 
active?

Or is there a "wrapper" command that runs a process and when that 
process exists
due to crashing or just exiting normally) that another process can be run.

Thanks,

Jerry

On Thu, Jan 10, 2008 at 10:22:56AM -0500, Jerry Geis
wrote:
> Is there a command that will monitor a process for exiting (crash or
> normal exit) and then execute another command based on the said
> process no longer being active?
You can use SNMP to do this.  It will set a flag in a certain OID which
you then need to monitor.  I _believe_ you may even be able to tell
snmpd itself to call a process, but I don't recall on that.

Check the man pages.
>
> Or is there a "wrapper" command that runs a process and when that
> process exists due to crashing or just exiting normally) that another
> process can be run.
You might look into something like daemontools[1].  It might be a
little overly complex.  You could certainly script something yourself.
However, daemontools are quite reliable.

Ray

[1]: http://cr.yp.to/daemontools.html

Jerry Geis wrote:
> Is there a command that will monitor a process for exiting (crash or 
> normal exit) and
> then execute another command based on the said process no longer being 
> active?
> 
> Or is there a "wrapper" command that runs a process and when that
> process exists
> due to crashing or just exiting normally) that another process can be run.
> 
> Thanks,
> 
> Jerry
Try monit.
http://tildeslash.com/monit/

The link seems to be down.
But the rpm is available on rpmforge and the manpage is excellent.

-- 
Regards,
Anup Shukla

Jerry Geis wrote:
> Is there a command that will monitor a process for exiting (crash or 
> normal exit) and
> then execute another command based on the said process no longer being 
> active?
> 
> Or is there a "wrapper" command that runs a process and when that
> process exists
> due to crashing or just exiting normally) that another process can be run.
> 
Why not use a shell script as a wrapper?  If you don't put something in 
the background with an & on the line, the next line will execute when/if 
the program started on the current line exits.  There are nearly always 
other copies of the shell running anyway so you get shared-text 
efficiency.  If you just want to keep restarting the same program, 
something like this should run forever.

while :
  do
   my_program
  done


-- 
   Les Mikesell
    lesmikesell at gmail.com

On 1/10/08, Jerry Geis <geisj at pagestation.com>
wrote:
> Is there a command that will monitor a process for exiting (crash or
> normal exit) and
> then execute another command based on the said process no longer being
> active?
If you want something simple, the wait(1) command can block until some
process specified by its PID terminates.

-- Daniel