* HOW TO distiguish between command input and forked subshell ?
[not found] <960905162314.ZM11373@admin.diego.netmanage.com>
@ 1996-09-07 16:30 ` C. v. Stuckrad
1996-09-16 7:07 ` Bart Schaefer
0 siblings, 1 reply; 2+ messages in thread
From: C. v. Stuckrad @ 1996-09-07 16:30 UTC (permalink / raw)
To: zsh-users
On Thu, 5 Sep 1996, Bart Schaefer ANSWERED:
> Subject: Re: HOW TO distiguish between command input and forked subshell ?
> On Sep 6, 12:47am, C. v. Stuckrad ASKED:
> > Subject: HOW TO distiguish between command input and forked subshell ?
> > Exactly, I want to have the function 'chpwd' give some output
> > if triggered by 'cd' or 'chdir' BUT TO GIVE NO OUTPUT
> > if triggered by cases like '... $(cd somewhere; ls)...'
*** this was exactly enough specified ***
> chpwd() {
> if [[ -t 1 ]]
> then
> print By golly, my standard output is a terminal.
> fi
> }
OK, thanks for explaining (again), and this works perfectly well
in this case of ... $(cd ...)... !
The User who aked was a typical beginner, who used a macro/function
chpwd () { ...to change x-window-title to the current dir... }
and now the title is no longer changed by cd-ing inside of $()
expansions. BUT if you just type '(cd somwhere; do_something)'
you again get the title changed to 'somewhere' instead of staying
where the zsh stood and stayed !
Does somebody see a chance to distinguish the two cases ?
I first thought $SHLVL, but it stays the same!
Does ...; ( something ) ; ...
the same as ... { something } ; ... ???
Again clueless (this time on zsh-users :-) Stucki
Christoph von Stuckrad * * | talk to | <stucki@math.fu-berlin.de> \
Freie Universitaet Berlin |/_* | nickname | ...!unido!fub!leibniz!stucki|
Fachbereich Mathematik, EDV |\ * | 'stucki' | Tel:+49 30 838-7545{9|8} |
Arnimallee 2-6/14195 Berlin * * | on IRC | Fax:+49 30 838-5913 /
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: HOW TO distiguish between command input and forked subshell ?
1996-09-07 16:30 ` HOW TO distiguish between command input and forked subshell ? C. v. Stuckrad
@ 1996-09-16 7:07 ` Bart Schaefer
0 siblings, 0 replies; 2+ messages in thread
From: Bart Schaefer @ 1996-09-16 7:07 UTC (permalink / raw)
To: C. v. Stuckrad, zsh-users
On Sep 7, 6:30pm, C. v. Stuckrad wrote:
} Subject: HOW TO distiguish between command input and forked subshell ?
}
} The User who aked was a typical beginner, who used a macro/function
} chpwd () { ...to change x-window-title to the current dir... }
} and now the title is no longer changed by cd-ing inside of $()
} expansions. BUT if you just type '(cd somwhere; do_something)'
} you again get the title changed to 'somewhere' instead of staying
} where the zsh stood and stayed !
Don't change the title bar in chpwd(). Change the title bar in precmd().
If you want to avoid changing it "too frequently" for some reason, use
if [[ ${oldPWD:=.} != $PWD ]]
then
# ... change title bar and ...
oldPWD=$PWD
fi
} Does somebody see a chance to distinguish the two cases ?
} I first thought $SHLVL, but it stays the same!
In older Bourne shells you used to be able to distinguish by using
foo=$$; (if [ $$ -ne $foo ] ... ; )
because $$ would change inside the subshell. But zsh doesn't do a new
getpid() for every $$ reference, so that doesn't work. (This causes
other problems, because you used to be able to have a subshell kill
itself with `kill -1 $$` but in zsh that kills the parent.)
I don't know of any way to detect subshell-ness, having played with
it a bit in the past.
--
Bart Schaefer Brass Lantern Enterprises
http://www.well.com/user/barts http://www.nbn.com/people/lantern
New male in /home/schaefer:
>N 2 Justin William Schaefer Sat May 11 03:43 53/4040 "Happy Birthday"
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1996-09-07 16:30 ` HOW TO distiguish between command input and forked subshell ? C. v. Stuckrad
1996-09-16 7:07 ` Bart Schaefer
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