Debian/Ubuntu Package Installation Shortcut

Alt-F2 then type

apt:packagename

Simple, quick, and should work in any window manager. Just remember that package names are case sensitive and almost always lowercase.

Here's an example where I install XBMC:

Then just click Install:

This example is with Ubuntu's default window manager, GNOME, but should work basically the same way in any other window manager, just not as pretty. *ducks*

Easy, automated backups with rdiff-backup

Let me start by saying rdiff-backup is exactly the tool I set out to find when looking for a backup solution. It makes use of librsync so you get all the goodness of the rsync remote-delta optimization algorithm, plus incremental backups. To top it off, your most recent backup is stored as a simple mirror so recovering your most recent backup of a given file is just a matter of (s)cp'ing it.

To setup automated, unattended backups (the holy grail of data backups) I used a good HOWTO guide for setting up unattended backups. so I won't duplicate that; I'll just summarize and detail the parts that are unique to Debian or ARM/embedded systems (I'm running Debian squeeze on a SheevaPlug). For simplicity, I'll use the same machine names as were used in the original HOWTO – kitty for the backup server and fishie for the machine to be backed up. I'm only backing up one home directory on fishie for a hypothetical user we'll call nemo.

1. First, install rdiff-backup on kittie and fishie:
   

   sudo apt-get install rdiff-backup

2. Create an account for your backup bot:
   

   adduser --system --group --disabled-login --disabled-password --home /var/backupbot backupbot

   My 1 TB USB hard drive is mounted at /var so that is where I place the home directory. This also follows the FHS guidelines.
3. Create a public/private key pair for backupbot, copy it to the authorized_keys file of nemo@fishie, then test it:
   

   sudo -s -u backupbot
   ssh-keygen -f ~backupbot/.ssh/id_fishie
   ssh-copy-id -i ~backupbot/.ssh/id_fishie.pub nemo@fishie
   ssh nemo@fishie

4. Assuming the above commands worked, you should now be logged in as nemo@fishie. Open an editor and prepend the following to the long line of gibberish that was just added to ~nemo/.ssh/authorized_keys
   

   command="rdiff-backup --server --restrict-read-only /home",from="kittie",no-port-forwarding,no-X11-forwarding,no-pty 

   Now any SSH session that is authenticated using this key will (1) automatically launch rdiff-backup in server mode and (2) have several SSH features disabled (for extra security).
5. As backupbot, open ~backupbot/.ssh/config (sudo -u backupbot emacs ~backupbot/.ssh/config) and enter the following:
   

   host nemo-backup
       hostname fishie
       user nemo
       identityfile /backup/.ssh/id_fishie
       compression no
       protocol 2

   Some notes about these options:
   
   • I don't use root to log into the remote machines because I'm only backing up home directories. This means you should take care to not to create files within your home directory that you do not have read access to (or at least keep them confined to one subdirectory so that rdiff-backup can skip them with a simple --exclude option). To find and fix any files that you may have already created while (e.g.) running as root use the following command:
     

     sudo find ~nemo -not -user nemo -exec chown nemo:nemo {} +

   • The first time I ran a backup I used 'compression yes'. I promise never to do that to you again, poor little SheevaPlug. If you have a slower link speed or a faster CPU then compression may make sense. For more optimization you may want to experiment with 'cipher blowfish' option. It can supposedly run at 88% of the speed of 'cipher none' but I haven't had a chance to play with it myself.
6. The last step is to automate the backup. Run sudo -u backupbot EDITOR=emacs crontab -e. Add the following crontab line:
   

   30 0 * * * rdiff-backup nemo-backup::/home/nemo /var/backupbot/nemo && rdiff-backup --remove-older-than 3M /var/backupbot/nemo && echo "Backup successful"

   This will run a backup every night at 12:30 AM and delete any incremental backups older than 3 months.

I'll do a follow up post on how I setup postfix with Gmail's SMTP servers. So that each user gets an email each morning with the status of the backup.

Debian RC Script Control

As a former Gentoo user, I had to learn the Ubuntu/Debian way to add service to a system runlevel. For my desktop, I never had to worry about it because, as usual with Ubuntu, a nice GUI is provided to manage startup services (System -> Administration -> Services). However when installing pyscrabble-server on my closet server I had to lookup the CLI tool for the job. (Note that I could have just used X11 forwarding to run the GUI tool, but that is just not nearly as cool and would have required lots of unnecessary GUI packages) It its simplest form, the comand to automatically start and stop /etc/init.d/SERVICE at startup and shutdown is simply:

sudo update-rc.d SERVICE defaults

From the man page:

If defaults is used then update-rc.d will make links to start the service in runlevels 2345 and to stop the service in runlevels 016.

For anything more complex, see the man page. Note that Debian has good bash completion support for the update-rc.d command.

If you're adding your own home-brew service, you can always just add commands to /etc/rc.local and make that file executable.