Re: Bash cannot kill itself?

[Chris F.A. Johnson]

On Wed, 30 Jun 2010, Clark J. Wang wrote:

> On Wed, Jun 30, 2010 at 12:38 PM, Chris F.A. Johnson
> <chris@cfajohnson.com>wrote:
> 
> > On Wed, 30 Jun 2010, Clark J. Wang wrote:
> >
> > > I have a bash script like this:
> > >
> > > #!/bin/bash
> > >
> > > trap 'echo killed by SIGALRM; exit 1' ALRM
> > >
> > > function wait_kill()
> > > {
> > >     sleep 5
> > >     kill -ALRM $$
> > > }
> > >
> > > wait_kill &
> > >
> > > sleep 3600
> > >
> > > ### END OF THE SCRIPT ###
> > >
> > > It does not work as I expected. The running script was not terminated
> > after
> > > 5 seconds. So what's wrong here?
> >
> >   $$ refers to the subshell.
> 
> 
> There's no subshell here, I think.

   The background process invoked by &.

> > Try:
> >
> > trap 'echo killed by SIGALRM; exit 1' ALRM
> >
> > function wait_kill()
> > {
> >    sleep 5
> >     kill -ALRM $pid
> > }
> >
> > pid=$$
> > wait_kill &
> >
> > sleep 3600
> >
> > --
> >   Chris F.A. Johnson, <http://cfajohnson.com>
> >   Author:
> >   Pro Bash Programming: Scripting the GNU/Linux Shell (2009, Apress)
> >   Shell Scripting Recipes: A Problem-Solution Approach (2005, Apress)
> >
> 

-- 
   Chris F.A. Johnson, <http://cfajohnson.com>
   Author:
   Pro Bash Programming: Scripting the GNU/Linux Shell (2009, Apress)
   Shell Scripting Recipes: A Problem-Solution Approach (2005, Apress)