inside the mind of a linux admin

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 […]

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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’ “-nn” makes it not lookup hostnames in DNS and service names (in /etc/services) for respectively faster and cleaner output. “-X” makes it print each packet in hex and ascii; that’s really […]

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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 […]

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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” […]

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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. […]

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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 […]

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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, […]

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Unhackable Security is a Linux security consulting firm specializing in a wide array of technologies and proven practices which make your server virtually unhackable. Ksplice is an extension of the Linux kernel which allows system administrators to apply security patches to a running kernel without having to reboot the operating system. Ksplice takes as input […]

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Firefox 9 Released – How to install on Ubuntu

Firefox 9 is now available — but unlike its previous rapid release forebears where not a lot changed, a huge feature has landed with the new version: the JavaScript engine now has type inference enabled. This simple switch has resulted in a 20-30% JS execution speed increase (PDF), putting JaegerMonkey back in line with Chrome’s […]

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Writing Python code to use MySQL

Python is a programming language that lets you work more quickly and integrate your systems more effectively. I’ve been programming primarily in Python lately, and had the need to open a socket to a MySQL database to pull data. By default, older versions of Python does not currently have a mySQL library that can easily […]

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