auto-exec on last command

auto-exec on last command

[Jörg Sommer]

Hi,

is it possible to advice zsh to replace its process (with exec) with the
process of the last command? I have many processes running they only
spawn the desired program. It would be more efficent to run these
processes with exec to don't keep the intermediat process of the shell.
Something like zsh -c 'setopt execlast; $myprog' or zsh -Xc '$myprog'
that runs the script 'exec $myprog'.

Regards, Jörg.
-- 
Wer eher stirbt ist länger tot.
                                                        (Un B. Kant)

Re: auto-exec on last command

[Bart Schaefer]

On Aug 21,  9:33pm, Jorg Sommer wrote:
}
} is it possible to advice zsh to replace its process (with exec) with
} the process of the last command?

How is the shell supposed to know what command is the "last" one?

} Something like zsh -c 'setopt execlast; $myprog' or zsh -Xc '$myprog'
} that runs the script 'exec $myprog'.

I'm a bit puzzled.  If you know to set the option or pass the flag, why
can't you just use "zsh -c 'exec ...' ?

Re: auto-exec on last command

[Jörg Sommer]

Bart Schaefer <schaefer@brasslantern.com> wrote:
> On Aug 21,  9:33pm, Jorg Sommer wrote:
>}
>} is it possible to advice zsh to replace its process (with exec) with
>} the process of the last command?
>
> How is the shell supposed to know what command is the "last" one?

Because the next token is EOF and no TRAPs are defined.

>} Something like zsh -c 'setopt execlast; $myprog' or zsh -Xc '$myprog'
>} that runs the script 'exec $myprog'.
>
> I'm a bit puzzled.  If you know to set the option or pass the flag, why
> can't you just use "zsh -c 'exec ...' ?

Take cron for example. Modifying the SHELL variable would be easy, but
changing all entries is much more work. Or the window manager IceWM. I
can configure the shell that's used to run subprocesses for menu entries,
but modifying all menu entries, and some of them are build by third party
scripts, is expensive.

Bye, Jörg.
-- 
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Re: auto-exec on last command

[Peter Stephenson]

On Sun, 21 Aug 2011 21:33:52 +0000 (UTC)
Jörg Sommer <joerg@alea.gnuu.de> wrote:
> is it possible to advice zsh to replace its process (with exec) with the
> process of the last command?

It does this automatically if it thinks the shell won't be needed again,
although there are probably complicated cases where it doesn't get this
right.

-- 
Peter Stephenson <p.w.stephenson@ntlworld.com>
Web page now at http://homepage.ntlworld.com/p.w.stephenson/