crontab + rsync problem

[Andrew Glen-Young]

On 11/10/2007, Luca Ferrari <fluca1978 at infinito.it> wrote:
> On Thursday 11 October 2007 Andrew Glen-Young's cat, walking on the keyboard,
> wrote:
> > I personally use separate user accounts, unique ssh keys without
> > passphrases and authorized_keys files with 'from' and 'command'
> > patterns in them. This, however, might not suit you.
>
> I didn't get this very weel, could you please explain me better? I have
> already separate accounts and ssh keys without passpharase, but I don't
> understan what you mean with "from" and"command".
>

These options to the 'authorized_keys' file is very well documented in
the sshd(8) man pages and will explain much better than I ever could.
Look in the 'AUTHORIZED_KEYS FILE FORMAT' section. You can place
restrictions for hosts that are allowed to use the key , etc. This is
only necessary if you're feeling paranoid ;-)

If you're using keys *without* passphrases, then I'm not sure why you
are required to use ssh-agent? You can edit your '~/.ssh/config' file
or run rsync with the '-e' switch to achieve the same thing.

example rsync command:

rsync -av -e "ssh -p 22000 -i ~/.ssh/somehost-id_rsa" \
  someuser at somehost.example.com:/path/to/dir /path/to/dest

example ~/.ssh/config:

Host somehost.example.com
    IdentityFile ~/.ssh/somehost-id_rsa
    Protocol 2
    User someuser
    Port 22000

$ ssh -v somehost.example.com
debug1: Reading configuration data /home/user/.ssh/config
debug1: Applying options for somehost.example.com
debug1: Applying options for *
debug1: Connecting to somehost.example.com [192.168.0.1] port 22000
[...]

- A.