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From: std-unix@ut-sally.UUCP
Newsgroups: mod.std.unix
Subject: Re: tail in 1003.2 Commands
Message-ID: <7001@ut-sally.UUCP>
Date: Thu, 29-Jan-87 18:09:35 EST
Article-I.D.: ut-sally.7001
Posted: Thu Jan 29 18:09:35 1987
Date-Received: Sat, 31-Jan-87 01:50:20 EST
References: <6710@ut-sally.UUCP> <6783@ut-sally.UUCP> <6882@ut-sally.UUCP> <6966@ut-sally.UUCP>
Organization: IEEE P1003 Portable Operating System for Computer Environments Committee
Lines: 37
Approved: jsq@sally.utexas.edu

From: guy%gorodish@Sun.COM (Guy Harris)
Date: 29 Jan 87 07:20:35 GMT
Reply-To: guy@sun.UUCP (Guy Harris)
Organization: Sun Microsystems, Mountain View

>>From: colonel@sunybcs.UUCP (Col. G. L. Sicherman)
>>I'd like to see a program that does what tail does, except that if
>>you say "tail +n" it skips the first n units.

	sed -n '<n>,$p'

will do the job quite nicely.

>>And how about a "head" with the same syntax as tail/trail?
>>("head xx file; tail xx file" = "cat file")
>
>Try 'dd bs=n skip=1' - actually, what you need is a 'line' modifier to
>dd, in addition to chars, blocks and k.

Well, 4BSD has such a "head" command, and writing one for systems
lacking it would probably take less work than adding a "line"
modifier to "dd" (which would be totally inappropriate for "dd", just
as "-v" is inappropriate for "cat").  On the other hand,

	sed -n '1,<n>p'

will do the job quite nicely here, too.  (I suspect it may still read
the rest of the file, but sticking in optimizations to avoid this are
left as an exercise to the reader.)

Let's not use 1003.2 as a chance to add every feature we want to some
UNIX command, or to tweak their behavior to fit something that seemed
convenient one day last month, or to add our favorite command.  The
commands standardized in 1003.2 should be *tools* - such as, to pick
a random example, "sed".

Volume-Number: Volume 9, Number 35