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From: rorex@locus.com (Phil Rorex)
Newsgroups: comp.unix.questions
Subject: Re: Can UNIX pipe connections be compiled?
Message-ID: <1991Jan24.022812.3033158@locus.com>
Date: 24 Jan 91 02:28:12 GMT
References: <1991Jan18.193234.216@rucs.runet.edu> <1991Jan19.040325.8815@druid.uucp>
Organization: Locus Computing Corporation, Inglewood, CA
Lines: 50

>In article <1991Jan18.193234.216@rucs.runet.edu> Dana Eckart writes:
>>Does there exist a piece of software (or is it even possible) to compile
>>a pipe?  In particular, suppose you had 
>>	ls -l | fgrep "Dec" | cut -f 4
>>is there anyway to compile the above pipeline so that the pieces can
>>communicate more quickly.  I am looking for a general solution, not
>>one that works only for the above example.
>
>
>I don't see how.  Any program that was created from the above line would
>have to do everything the shell does when it sees that line and that
>program has to be loaded and run as well.  If anything such a program
>would slow it down.
>
>Just a thought BTW - are you running out of memory?  If you are right

I agree.  Don't overlook this. ^^^^^^^^^^^^^^^^^^^^^  

>at the low limit you may be swapping when you get a large enough pipe.
>My motherboard died recently and I have been running on a borrowed one
>with less memory and I see a lot of slowdown with it. The swapping is
>quite noticeable.
>
>-- 
>D'Arcy J.M. Cain (darcy@druid)     |
>D'Arcy Cain Consulting             |   There's no government
>West Hill, Ontario, Canada         |   like no government!
>+1 416 281 6094                    |

I've split up many a long pipe because of excessive paging.

On a heavily loaded machine,
	ls -l > /tmp/tmp.$$.1
	fgrep "Dec" < /tmp/tmp.$$.1 > /tmp/tmp.$$.2
	cut -f 4 < tmp.$$.2
	rm /tmp/tmp.$$.[12] &
can get in and out before all the pieces of the pipeline
	ls -l | fgrep "Dec" | cut -f 4
ever even get loaded in.

BTW, I've found egrep to be faster than fgrep on the paging unix's I've been
on for scenario's like yours.   _    Your mileage may vary. 
        +1 213 337-5062        |_) |_  . |        ...!{ucla-se|uunet}!lcc!rorex
          Phillip Rorex        |   | ( | |        rorex@locus.com 
                    Disclaimer: I speak only for myself
-- 
				_
        +1 213 337-5062        |_) |_  . |        ...!{ucla-se|uunet}!lcc!rorex
          Phillip Rorex        |   | ( | |        rorex@locus.com 
                    Disclaimer: I speak only for myself