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Ubuntu: How to delete all of your old kernels

In Ubuntu 11.10 and newer versions, GRUB2 will display all kernels installed on your system at boot time. If you're like me, you probably get annoyed with a lengthy list of out of date kernels to scroll through in your GRUB boot menu.
Let's be real, no one really wants to boot a kernel from last year with bugs and vulnerabilities when you have nice new shiny kernels to choose from. Thankfully, the latest versions of GRUB2 installed in Ubuntu automatically display the latest kernel and hides the older kernels that you may have installed.

Encrypting synergy traffic via OpenSSL and stunnel

I use synergy to control several different linux systems in my office using a single keyboard and mouse.
The only issue I have with this software is it does not (yet?) natively support SSL encryption for your traffic. This is problematic when transmitting plain-text passwords between systems, which I do often.

OpenProj complains of Oracle as java vendor instead of Sun with latest version

Those of you who use OpenProj for project management on Linux may receive an erroneous error from the software application complaining that your Java vendor is "Oracle" rather than "Sun".
Obviously, they are one in the same , but the OpenProj software isn't smart enough to know this (as of the authoring date of this article, version 1.4).
Here's an easy fix to get around this and trick the application into working with the Oracle java installation.

tcpdump - dump all the packets

I too always forget the parameters for this and have to look them up in the man page, so:
tcpdump -nnXSs 0 'port 80'

How to shrink an ibdata1 file with minimal MySQL downtime

The default mySQL configuration for InnoDB database tables creates a massive storage file called 'ibdata1'. Basically, the ibdata1 file contains the table data of your InnoDB tables. In large production environments, this file can grow to be extremely large. On some of the servers I administer, I've seen this file exceed sizes of 30GB. Fixing the file size obviously has the effect of limiting the total amount of data which can be stored in InnoDB tables, so that's not a viable option.

Gnome3: replace gnome-screensaver with xscreensaver

GNOME 3's "screensaver" leaves much to be desired, and if you're an old school X user like myself, you probably just want the good ole' screensaver back. Here's how to install it using the following commands (this will also remove gnome-screensaver):
sudo apt-get remove gnome-screensaver
sudo apt-get install xscreensaver xscreensaver-gl-extra xscreensaver-data-extra
Then search for "Screensaver" in the menu and tweak its settings to your needs.
To add Xscreensaver to startup, open Startup Applications and add "xscreensaver -nosplash".

Source control != File system

If you find yourself wanting or considering checking binary files into your source control system (Git, SVN), you're doing it wrong.
Source control is optimized for tracking changes to source files. When you have multiple revisions of a source file, the system has stored the original file and the changes between revisions. This is good.

Mozilla Firefox 12 released, upgrade your Ubuntu today "unofficially"

Mozilla Firefox 12 has not yet been released, it is in Beta state at the moment, but it will bring features such as the ability to paste URLs in the download manager window, line numbers for the Page Source viewer, the title attribute supports line breaks, Find in Page improvemens to center search results, added column-fill CSS property, added support for the text-align-last CSS property, added experimental support for ECMAScript 6 Map and Set objects.

Validating Package Consistency by md5sum for Linux

Occasionally you just want a bit of piece of mind about your server or Linux install. You may suspect there is somebody who has hacked your server or even something changed by a package install that shouldn't have been. Heres a couple of ideas on how to do a quick ‘health’ check on he md5sum of binary packages.
Debian based people should install dlocate and use that
apt-get install dlocate
dlocate -md5check openssh-server
To force a fail try something like this:

Linux Protip: How to make a patch file

I've been doing Linux system administration for well over ten years, and I've used patch files often. I've never actually had the need to create one until today. To my surprise, I discovered how blatantly simple and easy it is. I've always assumed it was some sort of black magic involving unicorns and rainbows. Sure, there are more complex ways to do this but for most needs this will work for you.
Whats a patch?

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