1 .TH "FINDDUP" 1 "Mar 2010" "Francois Fleuret" "User Commands"
3 \" This man page was written by Francois Fleuret <francois@fleuret.org>
4 \" and is distributed under a Creative Commons Attribution-Share Alike
9 finddup \- Find files common to two directories (or not)
13 \fBfinddup\fP [OPTION]... DIR1 [[and:|not:]DIR2]
17 With a single directory argument, \fBfinddup\fP prints the duplicated
20 With two directories, it prints either the files common to both DIR1
21 and DIR2 or, with the `not:' prefix, the ones present in DIR1 and not
22 in DIR2. The and: prefix is assumed by default and necessary only if
23 you have a directory name starting with `not:'.
25 This command compares files by first comparing their sizes, hence goes
28 When looking for identical files, \fBfinddup\fP associates a group ID
29 to every content, and prints it along the file names. Use the \fB-g\fP
34 is virtually the same as
39 \fB-h\fR, \fB--help\fR
42 \fB-d\fR, \fB--ignore-dots\fR
43 ignore files and directories starting with a dot
45 \fB-0\fR, \fB--ignore-empty\fR
48 \fB-c\fR, \fB--hide-matchings\fR
49 do not show which files from DIR2 corresponds to files from DIR1
50 (hence, show only the files from DIR1 which have an identical twin in
53 \fB-g\fR, \fB--no-group-ids\fR
54 do not show the file group IDs
56 \fB-p\fR, \fB--show-progress\fR
57 show progress information in stderr
59 \fB-r\fR, \fB--real-paths\fR
60 show the real path of the files
62 \fB-i\fR, \fB--same-inodes-are-different\fR
63 files with same inode are considered as different
70 None known, probably many. Valgrind does not complain though.
72 The MD5 hashing is not satisfactory. It is computed for a file only if
73 the said file has to be read fully for a comparison (i.e. two files
74 match and we have to read them completely).
76 Hence, in practice lot of partial MD5s are computed, which costs a lot
77 of cpu and is useless. This often hurts more than it helps, hence it
78 is off by default. The only case when it should really be useful is
79 when you have plenty of different files of same size, and lot of
80 similar ones, which does not happen often.
82 Forcing the files to be read fully so that the MD5s are properly
83 computed is not okay neither, since it would fully read certain files,
84 even if we will never need their MD5s.
88 The format of the output should definitely be improved. Not clear how.
90 Their could be some fancy option to link two instances of the command
91 running on different machines to reduce network disk accesses. Again,
92 this may not help much, for the reason given above.
99 List duplicated files in directory ./blah/, show a progress bar,
100 ignore empty files, and ignore files and directories starting with a
104 .B finddup sources not:/mnt/backup
107 List all files found in \fB./sources/\fR which do not have
108 content-matching equivalent in \fB/mnt/backup/\fR.
111 .B finddup -g tralala cuicui
114 List groups of files with same content which exist both in
115 \fB./tralala/\fR and \fB./cuicui/\fR. Do not show group IDs, instead
116 write an empty lines between groups of files of same content.
120 Written by Francois Fleuret <francois@fleuret.org> and distributed
121 under the terms of the GNU General Public License version 3 as
122 published by the Free Software Foundation. This is free software: you
123 are free to change and redistribute it. There is NO WARRANTY, to the
124 extent permitted by law.