- Use a heuristic to bound memory and cpu usage, at the cost of

producing suboptimal diffs for large file containing lots of changes.
Switch heuristic off with -d/--minimal (GNU compatible). Some hints
from millert@.
- Improve performance by reducing the number of realloc(3) calls.

ok millert@ tedu@

1 files changed, 12 insertions, 7 deletions

diff --git a/usr.bin/diff/diff.1 b/usr.bin/diff/diff.1
index b88f170e43b..877c19c468a 100644
--- a/usr.bin/diff/diff.1
+++ b/usr.bin/diff/diff.1
@@ -1,4 +1,4 @@
-.\" $OpenBSD: diff.1,v 1.18 2003/07/22 01:23:51 millert Exp $
+.\" $OpenBSD: diff.1,v 1.19 2003/07/27 07:39:52 otto Exp $
 .\"
 .\" Copyright (c) 1980, 1990, 1993
 .\"	The Regents of the University of California.  All rights reserved.
@@ -37,7 +37,7 @@
 .Nd differential file and directory comparator
 .Sh SYNOPSIS
 .Nm diff
-.Op Fl abilqtTw
+.Op Fl abdilqtTw
 .Oo
 .Fl c | Fl e | Fl f |
 .Fl n | Fl u
@@ -45,21 +45,21 @@
 .Op Fl L Ar label
 .Ar file1 file2
 .Nm diff
-.Op Fl abilqtTw
+.Op Fl abdilqtTw
 .Op Fl L Ar label
 .Fl C Ar number
 .Ar file1 file2
 .Nm diff
-.Op Fl abilqtw
+.Op Fl abdilqtw
 .Fl D Ar string
 .Ar file1 file2
 .Nm diff
-.Op Fl abilqtTw
+.Op Fl abdilqtTw
 .Op Fl L Ar label
 .Fl U Ar number
 .Ar file1 file2
 .Nm diff
-.Op Fl abilNqtTw
+.Op Fl abdilNqtTw
 .Oo
 .Fl c | Fl e | Fl f |
 .Fl n | Fl u
@@ -105,7 +105,12 @@ are marked
 Lines which are changed from one file to the other are marked in
 both files with
 .Sq !\ \& .
-Changes which lie within 3 lines of each other are grouped together on output.
+Changes which lie within 3 lines of each other are grouped together on
+output.
+.It Fl d
+Try very hard to produce a diff as small as possible. This may consume a
+lot of processing power and memory when processing large files with
+many changes.
 .It Fl e
 Produces output in a form suitable as input for the editor utility,
 .Xr ed 1 ,