Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!asuvax!ncar!hsdndev!cmcl2!adm!smoke!gwyn
From: gwyn@smoke.brl.mil (Doug Gwyn)
Newsgroups: comp.unix.questions
Subject: Re: I'm learning UNIX and I have a simple question
Message-ID: <16470@smoke.brl.mil>
Date: 20 Jun 91 18:03:52 GMT
References: <jpope.677361841@sysp1>
Organization: U.S. Army Ballistic Research Laboratory, APG, MD.
Lines: 26

In article <jpope.677361841@sysp1> jpope@hq.af.mil (i991x) writes:
>In the UNIX that I use there is a command "who" which lists the users that
>are currently on the system (as well as which terminal, when they logged on,
>etc..).  The problem is that they are listed one user per line.
>I would like to strip off the first field (the id-name) and output to the
>screen four columns (four users per line instead of one) without the other
>information about where and when they logged in.

	who | awk '{print $1}' | sort -u | 4

where "4" is one of several links ("2" through "6") to the same
executable shell script that I maintain in one of the command directories:

	exec pr -t -w80 -`basename $0` $*

You can of course substitute "pr -t -w80 -4" for "4" in the above pipeline,
if you'd rather do that than create the useful commands "2" through "6".

There are other variations, using other commands to do essentially the
same jobs.  The commands are described in the UNIX user reference manual
in section 1; on many implementations one can also print a copy of the
manual entry on-line via the "man" command, as in "man 1 sort".

This example of exploiting the UNIX user environment is prototypical.
The first half of Kernighan and Pike's "The UNIX Programming Environment"
does a good job of teaching how to devise these things for yourself.