rdup is a utility inspired by rsync and the plan9 way of doing
backups. rdup itself does not backup anything. It only prints
a list of files that are changed, or all files in case of a null dump.
It also handles files that are removed, allowing for correct incremental
backups. All paths printed are absolute.
It works as follows, for a full dump
Crawl all directories, and print all the names found to standard output.
Write a filelist with all the names found when crawling.
Use this list to calculate the correct incremental dump.
And for incremental dumps
Read in the filelist that was written when doing a full dump.
Crawl all the directories again.
Diff 1. and 2. to get two lists; one of removed items and one
of added/modified items.
Write the removed items to standard output
Write the modified/new items to standard output.
Write a new filelist.
Touch the time stamp file.
is a internal list rdup writes to, to keep track of which files
are in a backup. If you don't want this (i.e. make a full
backup), use /dev/null here. The file /dev/null is handled
specially by rdup: if detected no new file list is written. This
is useful when only doing full backups and you want all files to be printed.
can be specified multiple times. These are the directories and files
you want to backup. If omitted it defaults to the current directory (.).
If the -N timestamp option is not given, all paths found are
printed. Only when a -N timestamp file is given, times can be
compared and an incremental output can be generated.
rdup prints a filelist to standard output.
Subsequent programs in a pipe line can be used to actually
implement to backup scheme. If FILELIST is empty or non existent all
files in DIR are dumped. This is the same as a null dump. After a run
a new FILELIST is written. No warning is given when FILELIST is an
existing file, it just gets overwritten by rdup. New runs will
print out only those files that have actually changed or are removed
since the last run, thereby making incremental backups possible.
Files are checked for changes by comparing the c-time (change time),
if this time is NEWER than the c-time of timestamp file the pathname is printed
to standard output. When files are removed they are also printed to
standard output, but they are prefixed with a '-'. See
below. The default format rdup uses is: "%p%T %b %m %u %g %l %s %n\n"
Note, that rdup also supports hashing of files, this makes it
possible to check the local hash with the hash of the backed up file.
All errors are written to standard error.
If the directory or file does not exist, they are skipped and a
warning is emitted.
The general idea is to be very UNIX like and create a bunch of simple programs
which each do a their specific thing very well. With rdup and a
small shell script (50 lines) one can implement encrypted and compressed
As rdup doesn't backup anything, the backup policy; what you
backup, how you backup, how often and how you restore; is all left
to the scripts.
Specify a printf-style format to use. See FORMAT below.
use the c_time of file timestamp as the timestamp to decide what to
include in the incremental backup list. If timestamp does not exist
a full dump is performed.
will create/touch timestamp after it has printed the file list.
This means if something goes wrong, you still have the original
As -N, but look at the m_time of timestamp.
Reverse the output of rdup. Tools accepting this ouput must
create leading directory as they see them. This option allows a script --
running as a normal user -- to put files in a directory which could have
0600 as its permission.
The file named 'file' contains a list of Perl-compatible regular
expressions (PCRE) , one per line, that rdup will use to
exclude names. A '#' at the start of the line can be used to signal a comment.
Empty lines are discarded. The -0 option also affects the
format of this file.
If a directory is excluded, rdup won't descend in that directory,
so all files in that directory are also excluded.
The directories leading up to the directory to be backed up can not
be excluded. If you use a command line like:
rdup /dev/null /home/miekg/bin
The directories '/home', '/home/miekg', '/home/miekg/bin' are always printed.
If you want to exclude the file '/home/miekg/blaat' you need to add
the following regular expression: '/home/miekg/blaat'.
If you want
to exclude all .mozilla/cache directories of all users you can
use '/home/.*/.mozilla/cache/.*'. This doesn't exclude the directory
itself and I'm assuming that the users' home directories are found
Also note that rdup does not print directories with a
Don't honor .nobackup files. Normally if such a file is found the
directory and all files containing it, are not
printed to standard output. Now they are.
Print the files' contents to standard output. This sets
the FORMAT string to: "%p%T %b %u %g %l %s\n%n%C"
Any file content is written in a block/chunk based manner. The
last block is signaled with a null block. A block start entry is
ascii and is formatted as follows: VVBLOCKBBBBB\n
Where 'VV' is the version, now '01', then the literal string 'BLOCK'
and then the amount of bytes, typical '08192'. And then a newline.
<START OF THE FIRST 8192 BYTES>01BLOCK00015
<ANOTHER 15 BYTES>01BLOCK00000
This option is used when streaming your backup to a remote machine.
Only print removed files; entries that start with a `-'. This
option unsets -m.
Only print modified/new files; entries that start with a `+'. This
option unsets -r.
Be more verbose.
When used once, processed .nobackup files will be
printed to standard error. When used twice each path will also be
printed to standard error. This is usefull in case of a remote
backup (-c) where the normal output is not seen. Using
tee(1) might even be better...
Don't output files larger than size bytes.
This can be used to limit the amount of data to be transferred when doing a remote backup.
This option only applies to files.
Delimit filelist with NULL's instead of a newline. Use '\0' in the
format string to change rdup's output.
Stay on the local filesystem.
Print rdup's version.
Give an overview of the options.
rm -f timestamp && rdup -N timestamp LIST DIR
A full-dump filelist is printed to standard output. And with:
rdup -N timestamp LIST DIR
An incremental dump filelist is printed. The file timestamp
is used to save the exact time of rdup's run. The file LIST is
used to calculate the correct incremental dump list, this is needed
for files that are removed, or have a different type.
The default format rdup uses is: "%p%T %b %u %g %l %s %n\n"
The following escape sequences are understood by rdup:
'p': '+' if file is new/modified, '-' if removed
'b': permission bits from lstat(2), octal in four digits
'm': the file mode bits, st_mode from lstat(2), decimal digits
'l': path name length
's': file size, zero if directory, major,minor for devices and
see CAVEATS for soft- and hardlinks.
'n': path name
'N': path name, but in case of a soft- or hardlink only
the link name.
't': time of modification (seconds from epoch)
'H': the SHA1 hash of the regular file, all zeros ("0") for all other types
'T': file type
- normal file, l symlink, h hardlink, d directory,
c character device, b block device, p named pipe
and s socket.
'C': the content of the file (none for all other types)
To delimit the output of rdup with NULLs you can use '\0' in the
rdup writes the FILELIST in the following format:
MODE DEV INODE LINk UID GID PATH_SIZE FILE_SIZE PATH
Where MODE is the st_mode from stat(2), DEV is the dev id as returned by
the stat call and INODE is the inode number - rdup needs this info
to decide if a directory is renamed. LINK is equal to 'h' for hardlinks,
other wise it is '*'. UID and GID are the numeric user and group id of
the file. PATH_SIZE is the length of PATH. FILE_SIZE the file size.
And finally PATH is the path of the file.
The default output generated by rdup is formatted like:
+|-TYPE BITS UID GID PATH_SIZE FILE_SIZE PATH
plus or minus, indicating whether PATH should added or removed.
the type of the file, see %T in FORMAT.
the permission of the file, this is a subset of the st_mode from
lstat(2). These are four octal digits.
the numerical user id of PATH. Note that if the first character of the
line is '-' (i.e. remove) the UID will be zero.
the numerical group id of PATH. Note that if the first character of the
line is '-' (i.e. remove) the GID will be zero.
the size of PATH.
the size of file pointed to by PATH. Note that if the first character of the line is '-'
(i.e. remove) the SIZE will be zero. For directories this size will
always be zero. Symbolic and hard links are handled differently, see
A typical example might look like this:
+- 0755 1000 1000 8 11288 bin/rdup
This example show that the file should be backed up, has a user
and group id of 1000, the length of the path is 8 bytes, the size
of the file it 11288 and it has "bin/rdup" as a path.
Directories are always printed by rdup.
OUTPUT FORMAT WITH -c
The output generated by rdup -c is formatted like:
Where aaa/a is a regular file containing the word 'hello\n'
Soft- and hardlinks are handled differently when using %n, if you don't
like this behavior use %N.
The PATH name is generated from the link's name and its target. A symlink like
/home/bin/blaat -> /home/bin/bliep
is printed as '/home/bin/blaat -> /home/bin/bliep'. The PATH_SIZE
is modified accordingly, where ' -> ' (4 characters) is also counted.
The FILE_SIZE is not needed for soft- or hardlinks, so it is set the
length of the link's name -- the part left of the ' ->', in this case the
length of '/home/bin/blaat'.
If rdup encounters a hardlink it is handled in the same way, but the
output type is set to 'h' instead of 'l'. A hardlink is only detected
if rdup finds a file with the same inode and device number as a previous
one, i.e. such hardlinks must be contained in your backup.
Again note: with '%N' only the link's name is printed. The FILE_SIZE is
still set to the length of the link's name.
For devices the size field (%s) is changed to hold the major,minor number of
the device. So if a major number is 8 and the minor number is 0 (under
Linux this is /dev/sda), its size will be 8,0. The numbers are
only separated with a comma `,'.
rdup return a zero exit code on success, otherwise 1 is returned.
rdup will abort if a file can not be concatenated, if a regular
expression can not be compiled or if a signal is received.
The next set of examples will all make a full dump -- because of the use
of /dev/null. See rdup-tr(1) for much more advanced examples.