.SH "DESCRIPTION"
With a single directory argument, \fBfinddup\fP prints the duplicated
-files found in it. 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 in DIR2. The and: prefix is assumed by default
-and necessary only if you have a directory name starting with `not:'.
+files found in it.
+
+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
+in DIR2. The and: prefix is assumed by default and necessary only if
+you have a directory name starting with `not:'.
This command compares files by first comparing their sizes, hence goes
reasonably fast.
-When looking for identical files, \fBfinddup\fP associates by default
-a group ID to every content, and prints it along the file names. Use
-the \fB-g\fP to switch it off.
+When looking for identical files, \fBfinddup\fP associates a group ID
+to every content, and prints it along the file names. Use the \fB-g\fP
+to switch it off.
Note that
.B finddup DIR
-is the same as
+is virtually the same as
.B finddup -i DIR DIR
.SH "OPTIONS"
.TP
-\fB-h\fR
+\fB-h\fR, \fB--help\fR
display help and exit
.TP
-\fB-d\fR
+\fB-d\fR, \fB--ignore-dots\fR
ignore files and directories starting with a dot
.TP
-\fB-0\fR
+\fB-0\fR, \fB--ignore-empty\fR
ignore empty files
.TP
-\fB-c\fR
+\fB-c\fR, \fB--hide-matchings\fR
do not show which files from DIR2 corresponds to files from DIR1
(hence, show only the files from DIR1 which have an identical twin in
DIR2)
.TP
-\fB-g\fR
+\fB-g\fR, \fB--no-group-ids\fR
do not show the file group IDs
.TP
-\fB-p\fR
+\fB-p\fR, \fB--show-progress\fR
show progress information in stderr
.TP
-\fB-r\fR
+\fB-r\fR, \fB--real-paths\fR
show the real path of the files
.TP
-\fB-i\fR
+\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.
+The MD5 hashing is not satisfactory. It is computed for a file only if
+the said file has to be read fully for a comparison (i.e. two files
+match and we have to read them completely).
+
+Hence, in practice lot of partial MD5s are computed, which costs a lot
+of cpu and is useless. This 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, and lot of
+similar ones, which does not happen often.
+
+Forcing the files to be read fully so that the MD5s are properly
+computed is not okay neither, since it would fully read certain files,
+even if we will never need their MD5s.
+
.SH "WISH LIST"
The format of the output should definitely be improved. Not clear how.
-The comparison algorithm could definitely use some MD5 kind of
-signature. However, I doubt it would improve speed much.
-
-Their should be some fancy option to link two instances of the command
-running on different machines to reduce network disk accesses.
+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.
.SH "EXAMPLES"
-.B finddup -cg blah something
+.B finddup -p0d blah
.fi
-List files found in \fB./blah/\fR which have a matching file with same
-content in \fB./something/\fR. Do not display the group IDs.
+List duplicated files in directory ./blah/, show a progress bar,
+ignore empty files, and ignore files and directories starting with a
+dot.
.P
.B finddup sources not:/mnt/backup
.fi
List all files found in \fB./sources/\fR which do not have
-content-matching equivalent in \fB/mnt/backup\fR.
+content-matching equivalent in \fB/mnt/backup/\fR.
.P
-.B finddup tralala cuicui
+.B finddup -g tralala cuicui
.fi
List groups of files with same content which exist both in
-\fB./tralala/\fR and \fB./cuicui/\fR.
+\fB./tralala/\fR and \fB./cuicui/\fR. Do not show group IDs, instead
+write an empty lines between groups of files of same content.
.SH "AUTHOR"
projects / finddup.git / blobdiff