#!/bin/sh -

# ttyuser - output the owner of the tty, else $USER else $LOGNAME
# Steve Kinzler, steve@kinzler.com, Feb 16
# https://kinzler.com/me/home.html#unix

ttyuser=`tty`
case "$ttyuser" in
/*)	ttyuser=`ls -l "$ttyuser" | awk '{ print $3 }'`;;
*)	ttyuser=;;
esac
echo "$ttyuser" | grep -s '^[A-Za-z][A-Za-z0-9]*$' > /dev/null
case "$?" in
0)	exec echo $ttyuser;;
*)	case "$*" in
	*-q*)	;;
	*)	echo "$0: warning, could not determine tty owner" 1>&2;;
	esac
	exec echo "${USER-$LOGNAME}";;
esac