.SH "SYNOPSIS"
-\fBfinddup\fP [OPTION]... DIR1 [[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 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.
+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
+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 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 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-c\fR
+\fB-0\fR, \fB--ignore-empty\fR
+ignore empty files
+.TP
+\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
-do not show the file group IDs (one group for each content)
+\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
-shows the real path of the files
+\fB-r\fR, \fB--real-paths\fR
+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
.SH "BUGS"
None known, probably many. Valgrind does not complain though.
-While not a bug per se, the format of the output should definitely be
-improved. Not clear how.
+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. This
+may not help much though.
.SH "EXAMPLES"
-.nf
-.B finddup -cg blah something
+
+.B finddup -p0d blah
.fi
-List files found in
-.B ./blah/
-which have a matching file with exact same content in
-.B ./something/
-without 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:./backup
+.B finddup sources not:/mnt/backup
.fi
-List all files found in
-.B ./sources/
-which do not have content-matching equivalent in
-.B ./backup.sources
+List all files found in \fB./sources/\fR which do not have
+content-matching equivalent in \fB/mnt/backup/\fR.
.P
-.B finddup ./tralala ./cuicui | sort -n
+.B finddup -g tralala cuicui
.fi
List groups of files with same content which exist both in
-.B ./tralala/
-and
-.B ./cuicui/
+\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