Ubuntu notes

I like Ubuntu. Every Linux distro has quirks, but I like working with Ubuntu quirks more than any others.

what security updates do I need?

Report which packages need security updates:

apt-get update
apt-get --dry-run upgrade | grep "^Inst" | grep "-security"

unknown group in statusoverride file

This has only happened to me once, but you may also see an error like this when using a package manager:

dpkg: syntax error: unknown group `Debian-exim' in statusoverride file 
E: Sub-process /usr/bin/dpkg returned an error code (2)

This is due to a faulty package removal. The package maintainer may have forgotten to remove the override when uninstalling a package. Usually it is safe to fix this by manually running something like the following:

dpkg-statoverride --remove /etc/exim4/passwd.client

How to unmark all packages marked to be upgraded in aptitude

If you hit 'U' to mark all upgradable packages to be you may change your mind and decide that you don't want to risk upgrading 20 different system critical packages. The trick is that it difficult to convince Aptitude to forget about these queued packages. You can select each one and hit '-' to unmark them, but that can be a drag is you have a lot of them in the list. Oddly, aptitude does not provide a way to unmark them all from inside the curses GUI, but you can easily do this from the command-line:

aptitude keep-all

selecting text in Aptitude

Aptitude takes control of the mouse which disables xterm mouse text selection. To override this simply hold SHIFT while you select text with the mouse.

supporting old releases in apt

Sometimes you find yourself needing to support an old release of Ubuntu and the original apt repositories are no longer supported or mirrored. Luckily, Ubuntu archives the old repositories at http://old-releases.ubuntu.com/ubuntu/dists/. You will need to update your /etc/apt/source.list file. For example, if you wanted to have access to edgy you would add the following to the top of sources.list:

deb http://old-releases.ubuntu.com/ubuntu/ edgy-updates main restricted
deb http://old-releases.ubuntu.com/ubuntu/ edgy-security main restricted
deb http://old-releases.ubuntu.com/ubuntu/ edgy main restricted
deb http://old-releases.ubuntu.com/ubuntu/ edgy universe
deb http://old-releases.ubuntu.com/ubuntu/ edgy-security universe

rc.d maintenance

See `update-rc.d` and `sysv-rc-conf`.

sysv-rc-conf

The `sysv-rc-conf` command similar to RedHat's `chkconfig`. It is intended as an easy user interface to the rc.d links. It’s a replacement for programs like ntsysv(8) or rcconf(8).

If you just run it with no options it will start a curses console GUI:

sysv-rc-conf

You can also perform all actions through CLI options similar to `chkconfig`, except there are no --add and --del options (just put the script in /etc/init.d and use the 'on' or 'off' commands below). The 'on' and 'off' commands work on run-level 2,3,4,5 by default.

sysv-rc-conf --list
sysv-rc-conf --list consolekit
sysv-rc-conf consolekit on
sysv-rc-conf consolekit off

update-rc.d

The `update-rc.d` command is more intended for use in scripts that manage rc.d links. Use this if you want to install new default links to a start-stop script. It will do nothing if any links already exist. A start-stop should have a comment section that starts with '### BEGIN INIT INFO'. This is used to define the default run level actions. To install a new start-stop script with the defaults use this:

update-rc.d foobar defaults

ConsoleKit -- AKA console-kit-daemon

You may see this daemon running and wonder what the hell it's for. It does a lot of stuff that I don't need at the moment. The simplest explanation is that ConsoleKit is used to implement "fast user switching" -- you know, where you can switch to a different user without logging the current user out. It is annoying that there are no man pages for it, but you can find some documentation under /usr/share/doc/consolekit. ConsoleKit was initially written by William Jon McCann. The homepage for it is here http://freedesktop.org/wiki/Software/ConsoleKit.

You can shutdown ConsoleKit -- this seems harmless:

/etc/init.d/consolekit stop