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* On 2005.04.27, in <20050427051010.GA13839@xxxxxxxx.xxxxxxx.xxx>,
* "Michael G Schwern" <schwern@xxxxx.xxx> wrote:
>
> You can see this in the tchrist's zen-like implementation of true in PPT.
> http://ppt.perl.org/commands/true/true.simple
When I settled on using bash as a login shell about 9 years ago, I used
a lot more of my computer's available resources than I do now and was
somewhat focused on eliminating anything that was not necessary. So I
put these into my bashrc, where they've been floating since:
true ()
{
return 0
}
false ()
{
return 255
}
yes ()
{
forever echo ${*-yes}
}
forever ()
{
while "$@"; do :; done
}
I didn't want to spare the fork() overhead. I think I found myself
far too often battling machines with full process tables, or deeply
entrenched in swap hell. (I miss those old SCSI disks. You could
always tell when one went to swap hell, from across the room. Now you
need software to tell you that, and we all know where that leads.)
There's a hate. Why can't I reserve some of those core resources for
emergency situations, like a minfree on memory? I don't have to worry
about full process tables anymore, and that's great, but we still get
full memory. I want priority memory, where priority == "I'm telling you
it's priority".
This is when I learned to hold some open interactive shells in reserve
on critical machines, so that if all else failed and I still couldn't
fork(), at least I could still exec reboot. The modern-day bad habit
consequence of this is that I never log out of machines unless the
terminal discipline gets fried and I can't fix it. So I have 103
screen(1) sessions open. Which I used to hate, because maneuvering
among more than a few screen sessions is a monstrous PITA, and screen
really needs some attention in that area, but now I've got workarounds
and who wants to go needling around in screen? What a wretched hive of
scum and villainy that is.
I also learned to renice -5 $$ all my root login shells as a matter of
routine.
Hey, when did bash make true and false builtins?
--
-D. dgc@xxxxxxxx.xxx NSIT University of Chicago
There's stuff above here
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