- Published:
- October 21, 2010 – 9:13 pm
- Author:
- By Dave
The first inkling that I had a problem with a DDoS (Distributed Denial of Service) attack was a note sent to my inbox:
lfd on server1.myhostname.com: High 5 minute load average alert – 89.14
My initial thought was that a site on my server was getting Slashdotted or encountering the Digg or Reddit effect. I run Chartbeat on several sites where this occasionally happens and I will usually get an alert from them first. A quick look at the Extended status page from Apache showed that I had a much different kind of problem.
Categories: System Administration
Tagged: apache, ddos, mod_evasive, sysadmin
- Published:
- September 22, 2010 – 10:28 pm
- Author:
- By Dave
It’s no secret that I’m a huge fan of Handbrake. After committing to copying my DVD collection to my storage array, I’ve tried and tested just about all software out there for converting video to H.264 with an emphasis on quality and speed. Many software packages have problems with quality or desynchronized audio, Handbrake is my hands-down favorite when it comes down to converting video — and that includes both free and commercial software.
One of the complaints I hear about Handbrake is that there are too many options. Well, the good news for someone looking for simplicity is that the built-in presets mostly take care of them for you. And for anyone who likes to dive into the nitty gritty of video compression, it also allows for a lot of tweaking to get the most out of your movie while maintaining small file sizes and high quality.
Read on for my full guide to Handbrake features.
Categories: Software,Windows
Tagged: dvd, encoding, video
- Published:
- September 20, 2010 – 12:21 pm
- Author:
- By Dave
I’m not trying to say I had anything to do with Google adding two-factor authentication to Google Apps. I’m really not. But on September 9th, MakeUseOf published an article named How To Secure Your Google Apps Account with Two Factor Authentication. In this article, I wrote: All of this brings up the question: why doesn’t Google enable a direct way to use two factor authentication with their Gmail, Calendar and other services? Many folks such as myself use Google services for all too many things in their lives, and that login is potentially the most important one of their online life. I would suggest that Google gets onto the security boat and enables this as an option for everyday folks. Today, 11 days later, Google released their own Two-Factor authentication scheme for Google Apps account (Premier, Education and Government). An example of accurate prognostication? Or just dumb luck? Either way,….
Categories: Google,Security,Software
Tagged: authentication, Google, Security
- Published:
- June 18, 2010 – 6:05 pm
- Author:
- By Dave
We received a tip from blog readers Christian and Michael for alternatives to the command to delete all directories older than a certain period of time. These both work in bash and can be used in scripts to clean up old backup directories or any situation where you need to delete old directories from the command line. From Christian: find /home/backup/ -maxdepth 1 -type d -mtime +7 -exec rm -r {} \; From Michael: find /home/backup/ -maxdepth 1 -type d -mtime +7 -exec echo “Removing Directory => {}” \; -exec rm -rf “{}” \; The first one works quietly, while the second one will display what is being deleted. These are probably faster than putting it into a for loop, so feel free to use whatever works best in your particular situation!
Categories: Linux,Shell,System Administration
Tagged: bash, oneliner, tips
- Published:
- February 13, 2010 – 1:12 pm
- Author:
- By Dave
The Bash command environment, which is the namesake of this blog, is very flexible in that it allows you to manipulate the filesystem in many ways. Awk and sed are very powerful tools that allow you to do this rename with a simple one line command. This post will walk you through doing this with a Comma Separated Value (CSV) file and also using a simple regular expression to rename many files.
Categories: Code Samples,Linux,Shell,System Administration
Tagged: awk, bash, csv
- Published:
- February 8, 2010 – 9:05 pm
- Author:
- By Dave
This is my admittedly minor but I hope useful contribution to the TinyOS development community. TinyOS is an Operating System and development framework for Wireless Sensor Networks and other platforms which has a small footprint and is very energy conscious. The TinyOS source code is available for free online for many operating systems, however it takes a long time to get the environment set up and it is not portable at all. I came across XubunTOS but it did not seem to be in active development anymore, so I endeavored to install TinyOS 2.1 and 2.x from source into a regular Ubuntu image. The most help came from Matt Keally’s Blog. While doing this, I thought it might be useful to many others who wish to develop in the TinyOS framework but might not have the skills necessary to install it. Therefore, I developed this VirtualBox image so that you can….
Categories: Programs,Software,Ubuntu
Tagged: tinyos, ubuntos, Ubuntu, virtualbox
- Published:
- January 31, 2010 – 9:53 pm
- Author:
- By Dave
It is very easy to create a random file using the linux command line. Much like the command to fill a file with all zeros, for example a 1 Meg file: dd if=/dev/zero of=zero.filename bs=1024 count=1000 You do the same using /dev/urandom: dd if=/dev/urandom of=random.filename bs=1024 count=1000 Resulting in a 1MB file: 1000+0 records in 1000+0 records out 1024000 bytes (1.0 MB) copied, 0.0294247 s, 34.8 MB/s This is transferring random data from the virtual device urandom to the output file. We use /dev/urandom instead of /dev/random because the /dev/random source generates random data very slowly. urandom is much faster at this but remains very random, if not quite a random as /dev/random. This should work with any system with dd and /dev/urandom.
Categories: Code Samples,Linux,Security,Shell
Tagged: command line, Linux, tips
