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== Old vs New Command Line Interface

Starting with `rdiff-backup` version 2.1, there have been two separate syntaxes for the command line interface, differentiated by the `--new` flag.
Legacy CLI commands follow the syntax `rdiff-backup [options…] [source…] [destination…]`, while the new CLI uses the syntax `rdiff-backup [global options…] action [action-specific options…] [locations…]`.
The functionality of the commands are the same, but for completeness the examples in this document will be given in both the old and new syntax side-by-side.

== Backing up

Simplest case: backup local directory `foo` to local directory `bar`.
`bar` will end up a copy of `foo`, except it will contain the directory foo/rdiff-backup-data, which will allow rdiff-backup to restore previous states.

----
rdiff-backup foo bar

rdiff-backup backup foo bar
----

Simple remote case: backup directory `/some/local-dir` to the directory `/whatever/remote-dir` on the machine hostname.net.
It uses ssh to open the necessary pipe to the remote copy of rdiff-backup.
Just like the above except one directory is on a remote computer.

----
rdiff-backup /some/local-dir hostname.net::/whatever/remote-dir

rdiff-backup backup /some/local-dir hostname.net::/whatever/remote-dir
----

This time the source directory is remote and the destination is local.
Also, we have specified the username on the remote host (by default ssh will attempt to log you in with the same username you have on the local host).

----
rdiff-backup user@hostname.net::/remote-dir local-dir

rdiff-backup backup user@hostname.net::/remote-dir local-dir
----

It is even possible for both the source and destination directories to be on other machines.
Below we have also added the `-v5` switch for greater verbosity (verbosity settings go from 0 to 9, with 3 as the default), and the `--print-statistics` switch so some statistics will be displayed at the end (even without this switch, the statistics will still be saved in the `rdiff-backup-data` directory).

----
rdiff-backup -v5 --print-statistics user1@host1::/source-dir user2@host2::/dest-dir

rdiff-backup -v5 backup --print-statistics user1@host1::/source-dir user2@host2::/dest-dir
----

== Restoring

Suppose earlier we have run `rdiff-backup foo bar`, with both foo and bar local.
We accidentally deleted `foo/dir` and now want to restore it from `bar/dir`.

----
cp -a bar/dir foo/dir
----

That's right, since rdiff-backup makes a mirror, we can retrieve files using standard commands like `cp`.

For the rest of the examples in the section, we will assume that the user has backed up with the command `rdiff-backup local-dir host.net::/remote-dir`.
Of course, in all these examples it would be equally possible to have the source being remote and the backup directory local.

In this case we can't use `cp` to copy `host.net::remote-dir/file` to `local-dir/file` because they are on different machines.
We can get rdiff-backup to restore the current version of that file using either of these:

----
rdiff-backup --restore-as-of now host.net::/remote-dir/file local-dir/file

rdiff-backup -r now host.net::/remote-dir/file local-dir/file

rdiff-backup host.net::/remote-dir/file local-dir/file

rdiff-backup restore --at now host.net::/remote-dir/file local-dir/file
----

The `--restore-as-of` (or `-r` for short) switch (`restore` action on the new CLI) tells rdiff-backup to restore instead of back up, and the `now` option indicates the current time.

But the main advantage of rdiff-backup is that it keeps version history.
This command restores `host.net::/remote-dir/file` as it was 10 days ago into a new location `/tmp/file`.

----
rdiff-backup -r 10D host.net::/remote-dir/file /tmp/file

rdiff-backup restore --at 10D host.net::/remote-dir/file /tmp/file
----

Other acceptable time strings include `5m4s` (5 minutes and 4 seconds) and `2002-03-05` (March 5th, 2002).
For more information, see the TIME FORMATS section of the manual page.

Finally, we can use rdiff-backup to restore directly from an increment file.
Increment files are stored in `host.net::/remote-dir/rdiff-backup-data/increments` and hold the previous versions of changed files.
If you specify one directly:

----
rdiff-backup host.net::/remote-dir/rdiff-backup-data/increments/file.2003-03-05T12:21:41-07:00.diff.gz local-dir/file

rdiff-backup restore host.net::/remote-dir/rdiff-backup-data/increments/file.2003-03-05T12:21:41-07:00.diff.gz local-dir/file
----

rdiff-backup will tell from the filename that it is an rdiff-backup increment file and thus enter restore mode.
Above the restored version is written to `local-dir/file`.

== Deleting older files

Although rdiff-backup tries to save space by only storing file differences, eventually space may run out in the destination directory.
rdiff-backup's `--remove-older-than` mode can be used to delete older increments.

This section assumes that rdiff-backup has been used in the past to back up to `host.net::/remote-dir`, but all commands would work locally too, if the hostname were omitted.

This commands deletes all information concerning file versions which have not been current for 2 weeks:

----
rdiff-backup --remove-older-than 2W host.net::/remote-dir

rdiff-backup remove increments --older-than 2W host.net::/remote-dir
----

NOTE: you might need to add the `--force` option if the selection leads to the removal of more than one increment at once.

Note that an existing file which hasn't changed for a year will still be preserved.
But a file which was deleted 15 days ago cannot be restored after this command is run.

As when restoring, there are a variety of ways to specify the time.
The `20B` below tells rdiff-backup to only preserve information from the last 20 rdiff-backup sessions.
(`nnB` syntax is only available in versions after 0.13.1.)

----
rdiff-backup --remove-older-than 20B host.net::/remote-dir

rdiff-backup remove increments --older-than 20B host.net::/remote-dir
----

== File selection with include/exclude options

Sometimes you don't want to back up all files.
The various `--include` and `--exclude` options can be used to select exactly which files to back up.
See the man page for a list of all the options and their definitions.

We have excluded `/proc`, `/tmp`, and `/mnt`.
`/proc` in particular should never be backed up.
Also, the source directory happens to be remote.

----
rdiff-backup --exclude /tmp --exclude /mnt --exclude /proc user@host.net::/ /backup/host.net

rdiff-backup backup --exclude /tmp --exclude /mnt --exclude /proc user@host.net::/ /backup/host.net
----

Multiple include and exclude options take precedence in the order they are given.
The following command would back up `/usr/local/bin` but not `/usr/bin`.

----
rdiff-backup --include /usr/local --exclude /usr / host.net::/backup

rdiff-backup backup --include /usr/local --exclude /usr / host.net::/backup
----

rdiff-backup uses rsync-like wildcards, where `+**+` matches any path and `+*+` matches any path without a `/` in it.
Thus this command:

----
rdiff-backup --include /usr/local --include /var --exclude '**' / /backup

rdiff-backup backup --include /usr/local --include /var --exclude '**' / /backup
----

backs up only the `/usr/local` and `/var` directories.
The single quotes `+''+` are not part of rdiff-backup and are only used because many shells will expand `+**+`.

Here is a more complicated example:

----
rdiff-backup --include '**txt' --exclude /usr/local/games --include /usr/local --exclude /usr --exclude /backup --exclude /proc / /backup

rdiff-backup backup --include '**txt' --exclude /usr/local/games --include /usr/local --exclude /usr --exclude /backup --exclude /proc / /backup
----

The above command will back up any file ending in `txt`, even `/usr/local/games/pong/scores.txt` because that include has highest precedence.
The contents of the directory `/usr/local/bin` will get backed up, but not `/usr/share` or `/usr/local/games/pong`.

rdiff-backup can also accept a list of files to be backed up.
If the file `include-list` contains these two lines:

----
/var
/usr/bin/gzip
----

Then this command:

----
rdiff-backup --include-filelist include-list --exclude '**' / /backup

rdiff-backup backup --include-filelist include-list --exclude '**' / /backup
----

would only back-up the files `/var`, `/usr`, `/usr/bin`, and `/usr/bin/gzip`, but not `/var/log` or `/usr/bin/gunzip`.
Note that this differs from the `--include` option, since `--include /var` would also match `/var/log`.

The same file list can contain both include and exclude files.
If we create a file called `include-list` that contains these lines:

----
**txt
- /usr/local/games
/usr/local
- /usr
- /backup
- /proc
----

Then the following command will do exactly the same thing as the complicated example above.

----
rdiff-backup --include-globbing-filelist include-list / /backup

rdiff-backup backup --include-globbing-filelist include-list / /backup
----

Above we have used `--include-globbing-filelist` instead of `--include-filelist` so that the lines would be interpreted as if they were specified on the command line.
Otherwise, for instance, `**txt` would be considered the name of a file, not a globbing string.

== Getting information about the backup directory

The following examples assume that you have run `rdiff-backup in-dir out-dir` in the past.

This command finds all new or old files which contain the string `frobniz`.

----
find out-dir -name '*frobniz*'
----

rdiff-backup doesn't obscure the names of files unless the file system doesn't support its length or certain characters, so often using traditional tools work well.

Either of these equivalent commands lists the times of the available versions of the file `out-dir/file`.
It may be useful if you need to restore an older version of `in-dir/file` but aren't sure which one.

----
rdiff-backup --list-increments out-dir/file
rdiff-backup -l out-dir/file

rdiff-backup list increments out-dir/file
----

The following command lists all the files under `out-dir/subdir` which has changed in the last 5 days.

----
rdiff-backup --list-changed-since 5D out-dir/subdir

rdiff-backup list files --changed-since 5D out-dir/subdir
----

This command lists all the files that were present in `out-dir/subdir` 5 days ago.
This includes files that have not changed recently as well as those that have been deleted in the last 5 days.

----
rdiff-backup --list-at-time 5D out-dir/subdir

rdiff-backup list files --at 5D out-dir/subdir
----

rdiff-backup writes one statistics file per session to the `out-dir/rdiff-backup-data` directory.
An average of the files can be displayed using the `--calculate-average` option and specifying the statistics files to use.

----
rdiff-backup --calculate-average out-dir/rdiff-backup-data/session_statistics*

rdiff-backup calculate --method average out-dir/rdiff-backup-data/session_statistics*
----

== Miscellaneous other commands

If you are having problems connecting to a remote host, the `--test-server` command may be useful.
This command simply verifies that there is a working rdiff-backup server on the remote side.

----
rdiff-backup --test-server hostname.net::/ignored

rdiff-backup test hostname.net::/somedir
----

IMPORTANT: starting with version 2.2, rdiff-backup also checks that it can access the given remote directory.
