Sam Trenholme's webpage
This article was posted to the Usenet group alt.hackers in 1995; any technical information is probably outdated.

Re: Just the hacks, ma'am


Article: 4932 of alt.hackers
Newsgroups: alt.hackers
From: A.Main@dcs.warwick.ac.uk (Zefram)
Subject: Re: Just the hacks, ma'am
X-Nntp-Posting-Host: stone
Message-ID: 1995Jun9.173657.13292@dcs.warwick.ac.uk
Sender: news@dcs.warwick.ac.uk (Network News)
Organization: Department of Computer Science, Warwick University, England
Date: Fri, 9 Jun 1995 17:36:57 GMT
Approved: a tad more so than that MAKE.MONEY.FAST post, one suspects
Lines: 49
Status: RO

Nice script.  Here's my version:

###############################
#!/bin/sh
#
#  lossage
#
#  DWF  6/6/95, drz 6/6/95 (but later that day), Zefram 1995-06-09
#
#  Usage:  lossage sitename [interval]
#

interval=260
case $# in
 1) ;;
 2) interval=$2;;
 *) echo "Usage: lossage sitename [interval]"; exit 1;;
esac

echo "                           Dead
Alive"
echo "Time                         |   1   2   3   4   5   6   7   8
9   |"
while true; do
 LOSSAGE=`ping -s $1 56 40 | fgrep "bytes from" | while read a;
 do echo -n '#'; done`
 echo "`date`  $LOSSAGE"
 sleep $interval
done
###############################

This uses slightly fewer processes, and doesn't rely on bash's built in
arithmetic.  You'll notice that the ping syntax is different; it's what works
on this system (SunOS 4.1), so you may need to modify it.

ObAncientHack:

This was waaaay back when I was using VMS, on a VAX mainframe.  Well, about
seven years back, to be a little more precise.

There was a command that would show all the processes running on the machine,
including the numeric GID and UID of the process' owner.  There was no option
to show this as a real username, and no command to convert between numeric and
alphanumeric UIDs.  (I believe there were system calls that would do it, but
the VMS application/OS interface is a bit of a nightmare, and I didn't need the
conversion very often.)  Inevitably, once or twice I wanted to know who was
running a particular process, so I came up with a hack that would turn a
numeric UID into a username.  I would create an ACL (Access Control List) on a
file, putting the mysterious UID into it.  Then save the ACL, and list it with
DIR /FULL.  It would show up as a username.

-zefram



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