Fixed the version number.

[finddup.git] / finddup.1

diff --git a/finddup.1 b/finddup.1
index 9cc21b4..62ab0b8 100644 (file)
--- a/finddup.1
+++ b/finddup.1
@@ -1,4 +1,4 @@
-.TH "FINDDUP" 1 "Mar 2010" "Francois Fleuret" "User Commands"
+.TH "FINDDUP" "1.0" "Mar 2010" "Francois Fleuret" "User Commands"

 
 \" This man page was written by Francois Fleuret <francois@fleuret.org>
 \" and is distributed under a Creative Commons Attribution-Share Alike
 
 \" This man page was written by Francois Fleuret <francois@fleuret.org>
 \" and is distributed under a Creative Commons Attribution-Share Alike


@@ -10,12 +10,13 @@ finddup \- Find files common to two directories (or not)
 
 .SH "SYNOPSIS"
 
 
 .SH "SYNOPSIS"
 

-\fBfinddup\fP [OPTION]... DIR1 [[and:|not:]DIR2]
+\fBfinddup\fP [OPTION]... [DIR1 [[and:|not:]DIR2]]

 
 .SH "DESCRIPTION"
 
 
 .SH "DESCRIPTION"
 

-With a single directory argument, \fBfinddup\fP prints the duplicated
-files found in it.
+With one directory as argument, \fBfinddup\fP prints the duplicated
+files found in it. If no directory is provided, it uses the current
+one as default.

 
 With two directories, it prints either the files common to both DIR1
 and DIR2 or, with the `not:' prefix, the ones present in DIR1 and not
 
 With two directories, it prints either the files common to both DIR1
 and DIR2 or, with the `not:' prefix, the ones present in DIR1 and not


@@ -61,26 +62,29 @@ show the real path of the files
 .TP
 \fB-i\fR, \fB--same-inodes-are-different\fR
 files with same inode are considered as different
 .TP
 \fB-i\fR, \fB--same-inodes-are-different\fR
 files with same inode are considered as different

-.TP
-\fB-m\fR, \fB--md5\fR
-use MD5 hashing

 
 .SH "BUGS"
 
 None known, probably many. Valgrind does not complain though.
 
 
 .SH "BUGS"
 
 None known, probably many. Valgrind does not complain though.
 

-The MD5 hashing often hurts more than it helps, hence it is off by
-default. The only case when it should really be useful is when you
-have plenty of different files of same size, which does not happen
-often.
+The current algorithm is dumb, as it does not use any hashing of the
+file content.
+
+Here are the things I tried, which did not help at all: (1) Computing
+md5s on the whole files, which is not satisfactory because files are
+often not read entirely, hence the md5s can not be properly computed,
+(2) computing XORs of the first 4, 16 and 256 bytes with rejection as
+soon as one does not match, (3) reading files in parts of increasing
+sizes so that rejection could be done with only a small fraction read
+when possible, (4) using mmap instead of open/read.

 
 .SH "WISH LIST"
 
 The format of the output should definitely be improved. Not clear how.
 
 Their could be some fancy option to link two instances of the command
 
 .SH "WISH LIST"
 
 The format of the output should definitely be improved. Not clear how.
 
 Their could be some fancy option to link two instances of the command

-running on different machines to reduce network disk accesses. Again,
-this may not help much, for the reason given above.
+running on different machines to reduce network disk accesses. This
+may not help much though.

 
 .SH "EXAMPLES"
 
 
 .SH "EXAMPLES"