: bash command help - nohup

[Patrick O'Callaghan]

On Fri, 2009-10-30 at 15:38 -0700, Suvayu Ali wrote:
> Hi Patrick,
> 
> Patrick O'Callaghan wrote:
> > On Fri, 2009-10-30 at 08:02 -0700, Suvayu Ali wrote:
> >>
> >> I often find nohup very unreliable. I have had jobs fail submitted with 
> >> nohup. I was thinking of switching to using screen. Maybe you could give 
> >> that a try?
> > 
> > Screen is not an option if you want to set up a long-running job and log
> > out. In what way has nohup failed on you? It's one of the oldest
> > commands in the Shell toolbox and I've never had a problem with it.
> > 
> > Note that it's often a good idea to run it thus:
> > 
> > nohup command > OUTPUT 2>&1 &
> 
> Whenever I have used nohup I have used it exactly the way you have 
> mentioned. And many times I later found out my job had failed when I had 
> logged out. Since then I have stopped using nohup and wanted to look 
> into screen. Until I do that I just don't log out any more unless I am 
> sure my job has finished. Maybe the unreliability I have experienced is 
> due to the versions of nohup I use (what ever comes as default with 
> Scientific Linux 4, thats way too old).

I guess commands under nohup can fail if they expect to send output to a
physical terminal, which presumably screen handles better. I can't think
what other reason could make them fail. Anything written to be used as a
filter shouldn't have this problem, but of course it depends what you're
doing.

poc