Bugfix echo, nmap hostgroup limit, kill error

ping_radar.sh

 #
 #You should have received a copy of the GNU General Public License
 #along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
+alias echo='/bin/echo -e'
 
 REFRESH=2
 HOSTS_FILES="$HOME/.hosts_scanner"
 	for pid in $(echo $pids)
 	do
 		echo killing $pid
-		kill $pid 2>/dev/null
+		kill $pid
 	done
 	for pid in $(echo $pids)
 	do
 	for pid in $(echo $cidr_pids $cidr_nmap_pid)
 	do
 		echo CIDR killing $pid
-		kill $pid 2>/dev/null
+		kill $pid
 		wait $pid
 		echo CIDR $pid killed
 	done
 
 	test -z "$4" && delay=5 || delay=$4
 	cidr_nmap_res=$(mktemp -t ping_radar_cidr_nmap.XXXXXXXX)
-	nmap_cmd="nmap -sP -oG $cidr_nmap_res --max-rate=15 $1"
+	nmap_cmd="nmap -sP -oG $cidr_nmap_res --max-rate=15 --max-hostgroup=5 $1"
 
 	trap clean_cidr 15