if [ $# -ne 1 ]; then
    echo "usage: $0 FILE"
    exit 1
fi

if [ -e $1 -a ! -f $1 ]; then
    echo "$1 is not a file"
fi

echo -n > $1

#simpler but longer
usersdup=$(who -q|head -n 1)
for i in $userdup; do
    echo $i >>userdup.txt
done
users=$(cat userdup|sort|uniq)



for user in $users; do
    echo "UTENTE $user" >> $1
    ps -u$user >> $1
done