bin/E: don't use non-portable grep -q

Author: rakoo

bin/E

@@ -12,9 +12,9 @@ B "$@"
 echo editing "$@"
 
 p=$(realpath $file)
-9p read acme/index | grep -q $p
-if [ $? -eq 0 ]; then
-	9p read acme/log 2> /dev/null | grep -q "del $p"
+win=$(9p read acme/index | awk -v p=$p '$0 ~ p {print $1}')
+if [ "$win" -gt 0 ]; then
+	$PLAN9/src/cmd/o.9p read acme/log | sed -n "/$win del/q"
 else
 	while sleep 1
 	do