:
##########################################################################
# Shellscript:	waitfor - wait for a user to log in
# Version    :	0.5 (beta)
# Author     :	Heiner Steven (heiner.steven@odn.de)
# Date       :	06.02.95
# SCCS-Id.   :	$Id: waitfor,v 1.1.1.1 1999/06/15 19:29:05 heiner Exp $
##########################################################################
# Changes
# 06.02.95 hs	Wait until user is logged in n times (0.2)
# 24.05.95 hs	Use "until" instead of "while" loop (0.3)
# 05.12.95 hs	Determine number of logins automatically (0.4)
# 26.03.96 hs	Adjust number of logins to wait for after terminated sessions
#		(thanks to kannan <kannan@mpd.tandem.com>) (0.5)
##########################################################################

PN=`basename $0`			# Program name
VER='0.5 (beta)'

# Determine mail program knowing "-s" argument
Mail=mail
[ -x /bin/mailx ] && Mail=mailx

: ${LOGNAME:=`whoami`}			# User to send mail to
SleepTime=10

Usage () {
    echo "$PN - wait for a user to log in, $VER (stv '95)
usage: $PN [-n count] user" >&2
    exit 1
}

Msg () {
    echo "$PN:" "$@" >&2
}

Fatal () { Msg "$@"; exit 1; }

set -- `getopt n:h "$@"` || Usage

n=0					# Wait until user is logged in n times
while [ $# -gt 0 ]
do
    case "$1" in
	-n)	n="$2"
	    case "$2" in
		*[!0-9]*)   Fatal "no positive integer number: $2";;
	    esac
	    shift;;
	--)	shift; break;;
	-h)	Usage;;
	-*)	Usage;;
	*)	break;;			# First file name
    esac
    shift
done

[ $# -eq 1 ] || Usage
User="$1"

# If the number of logins is not given, assume the current
# number + 1.
if [ ${n:=0} -eq 0 ]
then
    n=`who | awk '$1 == "'$User'"' | wc -l`
    [ ${n:=0} -gt 0 ] && Msg "Note: $User is already logged in" $n "time(s)"
    Sessions="$n"			# Current number of logins
    n=`expr $n + 1`
fi

until	k=`who | awk '$1 == "'$User'"' | wc -l`
	[ ${k:=0} -ge $n ]
do
    if [ $k -lt ${Sessions:=0} ]
    then
	# Session(s) terminated - adjust number of logins to wait for
	Sessions=$k
	n=`expr $k + 1`
    fi
    sleep $SleepTime
done

$Mail -s "$User is logged in at least $n time(s)" $LOGNAME <<!
`who | grep $User`
!