There are many ways to do what you want. The simplest is to use a pìpe:
tar zcvf - MyBackups | ssh user@server "cat > /path/to/backup/foo.tgz"
Here, the compression is being handled by
tar which calls
z flag). You can also use
7z, do this:
tar cf - MyBackups | 7za a -si -mx=9 -ms=on MyBackups.tar.7z |
ssh user@server "cat > /path/to/backup/foo.7z"
The best way, however, is probably
Rsync is a fast and extraordinarily versatile file copying tool. It can copy
locally, to/from another host over any remote shell, or to/from a remote rsync dae‐
mon. It offers a large number of options that control every aspect of its behavior
and permit very flexible specification of the set of files to be copied. It is
famous for its delta-transfer algorithm, which reduces the amount of data sent over
the network by sending only the differences between the source files and the exist‐
ing files in the destination. Rsync is widely used for backups and mirroring and
as an improved copy command for everyday use.
rsync has way too many options. It really is worth reading through them but they are scary at first sight. The ones you care about in this context though are:
-z, --compress compress file data during the transfer
--compress-level=NUM explicitly set compression level
With this option, rsync compresses the file data as it is sent to the desti‐
nation machine, which reduces the amount of data being transmitted --
something that is useful over a slow connection.
Note that this option typically achieves better compression ratios than can
be achieved by using a compressing remote shell or a compressing transport
because it takes advantage of the implicit information in the matching data
blocks that are not explicitly sent over the connection.
So, in your case, you would want something like this:
rsync -z MyBackups user@server:/path/to/backup/
The files would be compressed while in transit and arrive decompressed at the destination.
Some more choices:
scp itself can compress the data
-C Compression enable. Passes the -C flag to ssh(1) to
$ scp -C source user@server:/path/to/backup
There may be a way to get
7za to play nice but there is no point in doing so. The benefit of
rsync is that it will only copy the bits that have changed between the local and remote files. However, a small local change can result in a very different compressed file so there is no point in using
rsync for this. It just complicates matters with no benefit. Just use direct
ssh as shown above. If you really want to do this, you can try by giving a subshell as an argument to
rsync. On my system, I could not get this to work with
7za because it does not allow you to write compressed data to a terminal. Perhaps your implementation is different. Try something like (this does not work for me):
rsync $(tar cf - MyBackups | 7za a -an -txz -si -so) \
Another point is that
7z should not be used for backups on Linux. As stated on the
7z man page:
DO NOT USE the 7-zip format for backup purpose on Linux/Unix
- 7-zip does not store the owner/group of the file.