cmds: rename `ns` to `ns/cat`

sys/src/cmd/cmds.json

@@ -37,7 +37,6 @@
 			"mtime.c",
 			"mv.c",
 			"netstat.c",
-			"ns.c",
 			"p.c",
 			"pipefile.c",
 			"ps.c",
@@ -105,6 +104,7 @@
 			"hjfs/",
 			"hoc/",
 			"ndb/",
+			"ns/",
 			"rc/",
 			"rio/",
 			"sam/",

sys/src/cmd/ns/build.json

@@ -0,0 +1,11 @@
+{
+	"ns": {
+		"Include": [
+			"../cmd.json"
+		],
+		"Install": "/arch/$ARCH/cmd/ns/",
+		"SourceFilesCmd": [
+			"cat.c"
+		]
+	}
+}

sys/src/cmd/ns/cat.c

@@ -38,7 +38,7 @@ int	rflag;
 void
 usage(void)
 {
-	fprint(2, "usage: ns [-r] [pid]\n");
+	fprint(2, "usage: ns/cat [-r] [pid]\n");
 	exits("usage");
 }