weird zsh problem with background procs and scripts

weird zsh problem with background procs and scripts

[Tyler Spivey]

If you put the following into a loop it won't work. Is there a
workaround?

#!/bin/zsh
while :;do
ed &
jobs
sleep 1
done

this should launch a bunch of eds int he background, but only seems to
load one.
zsh -x shows that it's not even taking the &.

Re: weird zsh problem with background procs and scripts

[Anssi Saari]

On Sat, Aug 12, 2006 at 03:35:15PM -0700, Tyler Spivey wrote:
> If you put the following into a loop it won't work. Is there a
> workaround?
> 
> #!/bin/zsh
> while :;do
> ed &
> jobs
> sleep 1
> done
> 
> this should launch a bunch of eds int he background, but only seems to
> load one.
> zsh -x shows that it's not even taking the &.

Do you really want to launch a bunch of eds or is there something else
you're trying to accomplish? Ed happens to quit immediately when started
like that, so the script doesn't do much. You can for example start a
bunch of sleeps with that.

Re: weird zsh problem with background procs and scripts

[Bart Schaefer]

On Aug 12,  3:35pm, Tyler Spivey wrote:
}
} If you put the following into a loop it won't work. Is there a
} workaround?

What exactly do you expect to happen when you run "ed" in the background?
As far as I can tell it simply exits immediately, which would explain why
you only have one of them running at a time.

} zsh -x shows that it's not even taking the &.

You are misled.  "zsh -x" does not print the "&" because it doesn't print
*any* command separators.  Compare with:

#! /bin/zsh -f
while :;do
sleep 5 & sleep 6 &
jobs
sleep 1
done

Re: weird zsh problem with background procs and scripts

[Geoff Wing]

On Sunday 2006-08-13 08:34 +1000, Tyler Spivey output:
:If you put the following into a loop it won't work. Is there a
:workaround?
:#!/bin/zsh
:while :;do
:ed &
:jobs
:sleep 1
:done
:this should launch a bunch of eds int he background, but only seems to
:load one.

Works for me.  4.3.2-dev-1 on NetBSD.
Maybe your ed is exiting instead?

[3] 3050
[3]  + suspended (tty input)  ed
[3]  + suspended (tty input)  ed
[4] 8521
[4]  + suspended (tty input)  ed
[3]  - suspended (tty input)  ed
[4]  + suspended (tty input)  ed
[5] 29234
[5]  + suspended (tty input)  ed
[3]    suspended (tty input)  ed
[4]  - suspended (tty input)  ed
[5]  + suspended (tty input)  ed
...
and so on.

Regards,
Geoff