[lug] Bletcherous pipe, FIXME!
Jeffrey Haemer
jeffrey.haemer at gmail.com
Thu Apr 2 20:11:33 MDT 2009
> I'm sure bash has had two or three major versions since then. :)
Bash 4 was released in the last few weeks, and includes several fun new
features! I have seen it hiccup a couple of times, so it may not be ready
for mission-critical work today. The bash maintainer, Chet Ramey, fixes
shell bugs pretty fast, though. By the time it shows up, packaged, in your
distro, it should be fine.
I don't think there is a cost to using () over {}.
Not much if I'm just doing it once. I've had it bite me a little in big
loops. Contrast these:
sleep 1 && ps
{ sleep 1 && ps; }
( sleep 1 && ps ) # you should see an extra "-bash"
On the other hand, I do shell programming for programmer efficiency, not
code efficiency. :-)
The bigger difference is the environment. Contrast these
( cd /tmp; pwd ); pwd # you're back where you started
{ cd /tmp; pwd; }; pwd # you've moved
I've used subshells when my code started to become littered with "cd
$OLDPWD" or "cd ~-" .
--
Jeffrey Haemer <jeffrey.haemer at gmail.com>
720-837-8908 [cell]
303-997-1219 [Google Voice]
http://seejeffrun.blogspot.com
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