software

http://blog.nyaruka.com/skypes-crazy-regex-easter-egg You can use sed-like regular expression replacement in Skype chats!

http://www.nsrl.nist.gov/Downloads.htm The government maintains a database of cryptographic hashes which can be used to identify software.

http://www.scribd.com/doc/3501952/GNUs-Not-Eunuchs esr and rms slash.

http://www.youtube.com/watch?v=rOwMW6agpTI#t=6m50s A lecture on reverse engineering Stuxnet, a very sophisticated virus. This video is very entertaining and informative.

http://tartley.com/?p=1267 Git is simple!

http://en.wikipedia.org/wiki/Pixel_art_scaling_algorithms Multiple algorithms are available to upsample pixel art (frequently found in old video games). Wikipedia's article compares several algorithms and shows some impressive results. This paper was also recently released and also gives excellent results. The supplementary material link lets you visually compare different algorithms.

http://sysadvent.blogspot.com/2010/12/day-15-down-ls-rabbit-hole.html Tracing the steps needed to run ls.

http://www.lurklurk.org/linkers/linkers.html This is a pretty comprehensive introduction to linking in C and C++.

https://10.cloud.ubuntu.com/ Try out the server version of Ubuntu Linux for free on a VPS.

http://www.xtranormal.com/watch/6995033/mongo-db-is-web-scale Shards are the secret ingredient in the web scale sauce.