Re: Can Zsh do this for me?

[DervishD <raul@xxxxxxxxxxxx>]

    Hi Oliver :)

 * Oliver Kiddle <okiddle@xxxxxxxxxxx> dixit:
> > Right know, it can be written like this:
> >     ps xh | grep name | tr -s " " | cut -d " " -f 2
> This doesn't seem to work for PIDs >= 10000 where there is no initial
> space in the ps listing.

    Oh, yes, you're true, it was just a quick hack, not a good work ;))
The point was the four processes neeced for this, and your answer
below. Thanks a lot!!

> > get the process ID using the command name, or if I can write the
> > above pipeline in a shorter form using some Zsh capability.
> You can write the command-line as:
>     ${${${(M)${(f)"$(ps xh)"}:#*$name*}## #}%% *}
> (M) and :# does the grep. ## # removes initial space and the %% * does
> the job of cut.
> Use $~name if you'd like to use patterns for name. And if you only want
> one PID, use [1] on the end of it all.

    That's great! A very good example of what I was looking for: the
power of Zsh to do things faster ;)))) Right now I don't understand
the entire line (but I'm new to expansions...), but I will take a
look at the manual. Thanks a lot, truly :)

> >     BTW, I want to write a 'ps' command on my own because I don't
> > like the procps one available for Linux, nor the others out there,
> > and I think that with the zsh/stat module I could do it in a shell
> > script :)))
> I'm not quite sure how you'd do that using zsh/stat (using /proc?) but
> good luck with it.

    The point is to examine /proc. Some of the things can be done
using 'cat' and the like, but a couple of them must be done with the
stat syscall, and maybe zsh/mapfile to read the file contents in an
easy way. Really, Zsh is just incredible :)

    Raúl Núñez de Arenas Coronado

-- 
Linux Registered User 88736
http://www.pleyades.net & http://raul.pleyades.net/