Month: June 2006

Free remote backup: passwordless SSH + Rsync

If you’ve always wanted to backup your files to a remote server, but never really knew how – here’s a quick and easy way to do it:

1. Create a passwordless SSH setup
Login into your account on your [Linux, Unix, BSD, OS X] system. Type in

ssh-keygen -t dsa

Hit Enter three times.

This will create a .ssh directory in your home directory including some special encrypted files. Then type this – replacing the bits in bold with your own details

ssh ‘test -d .ssh || mkdir -m 0700 .ssh ; cat >> .ssh/authorized_keys && chmod 0600 .ssh/*’ < ~/.ssh/

If you’re asked for a password, type in the password for that you created.

Test your setup by typing:


If it logs in without asking you for a password – you’re done with that part! If not, try googling or mail me and I’ll try to help you out.

If you want to add more authorized keys – like from other users, just add a number to the end of authorized_keys – like so:

ssh ‘test -d .ssh || mkdir -m 0700 .ssh ; cat >> .ssh/authorized_keys2 && chmod 0600 .ssh/*’ < ~/.ssh/

Test it out by typing:


2. Back it up

Once that’s done, you need to set up rsync to back up your files. Type something like this:

rsync -e ssh -avz –delete /mydir/to_backup_up/ >> ~/backup.log

Replace (a) /mydir/to_backup_up/ with the directory you want to backup (b) with your username and host details (c) /mydir/backup with the remote folder that you will be backing your data up to and (d) ~/backup.log with the name of the file you want to log the output to.

If you want to automate this, type crontab -e and then add this:

30 * * * * rsync -e ssh -avz –delete /mydir/to_backup_up/ >> ~/backup.log

Replace all the bits in bold, save it and then this should backup your data every 30 mins.


I call bullshit on the OED

So there I was, casually glancing through a list of some hip’n’tasty neologisms breaking into the charts on Ask Oxford when I came across something absolutely and utterly ridiculous. Tell me if you spot anything wrong with this sentence:

Bluesnarfing: the illicit accessing of data from an electronic device such as a mobile phone, PDA, or computer using a Bluetooth® short-range wireless interconnection. The word made headlines when Bluesnarfers targeted the actress Paris Hilton and embarassingly made the electronic contacts list on her mobile available on the Net.

Uh. Excuse me? What? Paris Hilton’s T-Mobile Sidekick did NOT even have Bluetooth. Unlike most devices, the Sidekick handily backs up itself to a server-side repository – which the “Bluesnarfers” managed to “hack” into (in reality, they just guessed her password). I really wish that Catherine Soanes had bothered to read Peter Rojas’ lucid debunking of this incident in Engadget a few short months earlier. Oxford English Dictionary, you need a solid dose of fact-checking.

Speaking at Where 2.0, hanging at Hyperlinked Society.

Giant 2005/6 conference recap coming soon. In the meantime – I’m speaking at O’Reilly’s Where 2.0 Conference in San Francisco next week. I’m really excited about this conference – I was so bummed I had to miss it last year due to visa issue. I’m also speaking right at the tail-end of a trifecta of mobile locative social people including Walt Doyle from uLocate and Shawn Conahan from Intercasting.

Check out the schedule and give me a shout if you want to meet up.

I’m also hanging out at the Hyperlinked Society conference organized by Joseph Turow in Philadelphia later this week which promises to be tons of hypertextual fun. UPDATE: Couldn’t make this one – Dan is currently enjoying this conference at his alma mater.