Me on Stuff

This image was posted to Digg a couple of days ago:

After that these were posted to a FreeBSD IRC channel:

The first two aren’t so good but the last shows you exactly why you should use BSD.

I feel like having a rant on using /bin/bash in scripts so here it is:

DON’T USE /bin/bash IN SHELL SCRIPTS EVER.
If bash must be used for the script use “#!/usr/bin/env bash” otherwise use “#!/bin/sh”.

The reason is not everyone has bash installed as /bin/bash where if /bin/sh is not there the admin is asking for punishment.

The env trick works with bash wherever it is installed. eg. FreeBSD packages install bash to /usr/local/bin/bash, NetBSD installs it to /usr/pkg/bin/bash (I think, I don’t have a NetBSD system handy).

Perl and Python are the same. There might be a link from /usr/bin/perl to /usr/local/bin/perl in FreeBSD but that’s just because there used to be a copy of perl in the base system. There is no such link for python, You need to use “#!/usr/bin/env python”.

I’ve been looking at delta packages for Debian based systems more tonight.

Early tests seem to point to generating a delta of the data.tar file contained within the archive[1].

I tested the xbase-clients package from Ubuntu 4.10.
Each .deb file is around 1.9M each.
* A bsdiff of the 2 .deb files generates a 1.7M file [2]
* A bsdiff of the 2 data.tar.gz (the actual package) files was about the same
* But bsdiff produced a 78k diff when I gunziped each data.tar.gz

I will now investigate with more packages from my download cache if this is the case with other packages or if this was just a fluke.

[1] .deb files can be extracted with “ar -x file”
[2] gzip will introduce a cascading effect with every change making any binary update system ineffective if it relies on finding any common sections (e.g. bsdiff, rsync)

Ubuntu is currently deciding it will freeze everything in X except the mouse at random times.

This is very rare as it has only happened once before over a month ago. I will have to have a look at it with ssh if it happens again and will let me get in.

I decided to pre-download the updates for Ubuntu 5.04.

apt-get makes this an easy task as all I did was:

• create a new sources.list with only hoary resporitories
• sudo apt-get -o Dir::Etc::SourceList=./sources.list –just-print upgrade
• sudo apt-get -o Dir::Etc::SourceList=./sources.list -d update

The –just-print may not have been needed but I added it as I wasn’t sure and didn’t wan’t to kill my current system as I’m on dialup.

Now I just have to wait for about 240Mb of packages to download, if only they used delta packages (packages containing only the changes) or just send the deltas to the version released (just the changes between the package files). Both couls be obtained with bsdiff & bspatch