Blog :: 2011/05/...

How to unblock an IP which was blocked by denyhosts
Posted 2011/05/24
Denyhosts is a program for blocking an IP address after a number of failed ssh connection attempts. This is a very simple way to stop ssh brute force attacks on your machines. Every now and then a user manages to get an IP blocked by typing their password in incorrectly [...]
Merging SVN feature branches
Posted 2011/05/18
I make all major software changes in an SVN feature branch but I can never quite remember how to merge the branch back into trunk. Check out a clean version of trunk and then use this recipe: svn merge https:/// . (All on one line). 999 is the revision number when you [...]
IEEE Cluster 2011 paper submitted
Posted 2011/05/09
This evening we submitted the research paper I have been helping write over the past few weeks. Had to dig out my LaTeX knowledge which has been dormant since 2008. CLuster get back to you relatively quickly about submissions, which is nice. Now time to switch to a presentation for IPDPS. [...]
Non-root changing cpufreq in Linux
Posted 2011/05/07
We let collaborators onto our test cluster to do some power aware research. One thing they always want to do is change the CPU frequency. Rather than give everyone sudo we let any user on the machine change the frequency. This is done with a little bit of chmod magic: Edit [...]
Bulk password changes
Posted 2011/05/06
I recently had to create a batch of new user account under Linux. I already had a nice script for generating a hard password but I needed to set them on mass. Reading man passwd I found the section about using it in a script: --stdin [...]
Excel charts to LaTeX
Posted 2011/05/03
I am working on a paper with one of our students. He has his draft in Word, with the charts in Excel. It is time to get the paper into LaTeX so he is charged with exporting the charts into a format I can consume. The best format is EPS [...]