.SH "SYNOPSIS"
-\fBfinddup\fP [OPTION]... DIR1 [[and:|not:]DIR2]
+\fBfinddup\fP [OPTION]... [DIR1 [[and:|not:]DIR2]]
.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
None known, probably many. Valgrind does not complain though.
-The current algorithm is dumb, that is it does not use any hashing of
-the file content. I tried md5 on the whole file, which is not
-satisfactory because files are often never read entirely hence the md5
-can not be properly computed. I also tried XOR of the first 4, 16 and
-256 bytes with rejection as soon as one does not match. Did not help
-either.
+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 never read entirely hence the md5s can not be properly computed,
+(2) computing XOR of the first 4, 16 and 256 bytes with rejection as
+soon as one does not match, (3) reading parts of the files of
+increasing sizes so that rejection could be done with a small fraction
+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
-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"
projects / finddup.git / blobdiff