Document --line-buffered

ok jmc@

grep.1

@@ -1,4 +1,4 @@
-.\"	$OpenBSD: grep.1,v 1.22 2004/01/19 16:26:03 otto Exp $
+.\"	$OpenBSD: grep.1,v 1.23 2004/03/15 08:54:27 tedu Exp $
 .\" Copyright (c) 1980, 1990, 1993
 .\"	The Regents of the University of California.  All rights reserved.
 .\"
@@ -40,6 +40,7 @@
 .Op Fl CEFGHILPRSUVZabchilnoqsvwx
 .Op Fl -context Ns Op = Ns Ar num
 .Op Fl -binary-files Ns = Ns Ar value
+.Op Fl -line-buffered
 .Op Fl e Ar pattern
 .Op Fl f Ar file
 .Op Ar pattern
@@ -229,6 +230,12 @@ do not search binary files;
 and
 .Ar text ,
 treat all files as text.
+.Sm off
+.It Fl Fl line-buffered
+.Sm on
+Force output to be line buffered.
+By default, output is line buffered when standard output is a terminal
+and block buffered otherwise.
 .Pp
 .El
 If no file arguments are specified, the standard input is used.