Various fixes.

	B - fixed usage, DISPLAY :0 vs :0.0
	9term - fixed various terminal things
	rc - notice traps in Read
	_p9dir - only run disk code for disks
	dirread - getdirentries on FreeBSD and Linux
		are different w.r.t. meaning of off.
	notify - set up so signals interrupt system calls
	bprint - use bfmt.
diff --git a/bin/B b/bin/B
index a835167..411bcef 100755
--- a/bin/B
+++ b/bin/B
@@ -2,7 +2,7 @@
 
 if [ $# -eq 0 ]
 then
-	echo 'usage: B cmd...' 2>&1
+	echo 'usage: B file...' 2>&1
 	exit 1
 fi
 
@@ -10,6 +10,10 @@
 then
 	sam="/tmp/.sam.$USER"
 else
+	if [ "$DISPLAY" = ":0" ]
+	then
+		DISPLAY=:0.0
+	fi
 	sam="/tmp/.sam.$USER.$DISPLAY"
 fi