shell pipeline to reverse the order of lines.

Ned Nowotny ned at pebbles.cad.mcc.com
Sat Mar 2 07:18:26 AEST 1991


In article <2775 at kraftbus.cs.tu-berlin.de> net at opal.cs.tu-berlin.de (Oliver Laumann) writes:
=>In article <19079 at rpp386.cactus.org> jfh at rpp386.cactus.org (John F Haugh II) writes:
=>> >Considering that the `tail' command under vanilla BSD (at least 4.2 and
=>> >4.3 BSD) has this `feature' I wouldn't call it non-standard.  After all,
=>> >`tail' is a BSD command.
=>> 
=>> What would you prefer to call a feature which does not exist on all
=>> systems that have the command? 
=>
=>A vendor is free to put a version of `ls' on their UNIX port that
=>doesn't support the -l option any longer.  Does this make `ls -l'
=>non-standard?  Certainly not.
=>
=>> What would you prefer to call a command which may not exist on all systems?
=>
=>The fact that it may not exist on *all* systems is irrelevant.  I'm sure
=>that for almost any UNIX command (except maybe date, ls, etc.) you will
=>be able to find a system where this command does not exist.
=>
=>> As for being a ``BSD'' feature, I've yet to see a UNIX system without
=>> the command,
=>
=>Why do you think `tail' is under /usr/ucb (on those systems that have
=>a /usr/ucb)?  If the commands under /usr/ucb are not BSD commands,
=>then what *is* a BSD command?

I think you might find it there because that version of tail is a BSD version
which supports the -r flag.  However, that does not make tail a BSD command.
In fact, tail has been a standard UNIX command in every flavor of UNIX of which
I am aware since at least version 7.  To quote the 7th edition manual set:

NAME
	tail - deliver the last part of a file
SYNOPSIS
	tail [ +/-number[lbc] ] [ file ]
.
.
.

Ned Nowotny, MCC CAD Program, Box 200195, Austin, TX  78720  Ph: (512) 338-3715
ARPA: ned at mcc.com                   UUCP: ...!cs.utexas.edu!milano!cadillac!ned
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