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From: brnstnd@kramden.acf.nyu.edu (Dan Bernstein)
Newsgroups: comp.unix.questions
Subject: Re: edit first line of long file
Message-ID: <4597:Oct2321:44:2190@kramden.acf.nyu.edu>
Date: 23 Oct 90 21:44:21 GMT
References: <27338@shamash.cdc.com> <568@inews.intel.com>
Organization: IR
Lines: 28

In article <568@inews.intel.com> bhoughto@cmdnfs.intel.com (Blair P. Houghton) writes:
> In article <27338@shamash.cdc.com> ddh@dash@udev.cdc.com (Dan Horsfall) writes:
> >Plan A: pass the whole file thru sed, qualifing the search string
> >as "1s/.../.../"; sed will look at each line of the file.
> sed is the way.

No, it's not. Try head -1 | sed 's/.../.../'; cat.

> Anything else
> would involve multiple exec's and pipes and several context
> switches for each character of data, and then you get
> process and I/O collisions.

Hyperbole. No sane program does several context switches for each
character of data, and ``process and I/O collisions'' don't exist. sed
does much more processing on each character than cat does. On this
machine, sed is more than 12 times slower than cat.

> I'll predict nothing (except
> perhaps awk or certainly perl or C) would be faster than
> the sed line, and by posting to the net you've just cost
> yourself and the world more time, bytes, and money than any
> of these choices could possibly be worth.

Your prediction is wrong, and it's the hope of everyone who participates
in technical discussions that information received is worth money spent.

---Dan