Category: Computer Tips

Matplotlib ValueError on LogNorm plots

I was getting the error ValueError: Data has no positive values, and therefore can not be log-scaled. The issue is that I was setting vmin=0 in my pcolormesh() plot. By setting vmin=1 or some small positive value, your plots will work with norm=LogNorm() as expected.

Find text string in file

I save a script named “findtext” that will look for specific text you want inside any file smaller than a maximum size (avoiding searching huge binary file) you can find this and several other useful scripts at

Find Gmail email with any attachment e.g. PDF

You can see for the types of advanced searches you can do with Gmail. For example, if I want to find all PDFs I sent to, I type in Gmail search filename:pdf or to find any email I sent to with any attachment: has:attachment

Ralink RT2800 Warning TX status “fix”

I have some of the ubiquitous USB Wifi sticks with a chipset using the Ralink rt2800 driver. I noticed that while it works fine, I got a lot of dmesg errors like: rt2800usb_txdone: Warning – Got TX status for an empty queue 2, dropping rt2800usb_entry_txstatus_timeout: Warning – TX status timeout for entry 14 in queue […]

Fixing SSH Access Denied for Github

Github suggests that you use the SSH Agent, but even that may not work when you have a lot of SSH keys. You need to setup your ~/.ssh/config file so that SSH to uses the correct SSH Public Key the first time. Here’s how. nano ~/.ssh/config and add the lines Host Hostname […]

Restarting Unity desktop in Ubuntu

If your desktop seems to freeze for more than a few seconds, trying pressing together the keys Ctrl Alt F1 and then login with your username and password, and type unity & disown This will leave your desktop/apps all as they were while fixing the broken state. To just restart the whole Unity desktop (which […]

Updating BIOS in Gigabyte GA-Q87M-D2H to handle Haswell Refresh processor

This otherwise great motherboard is currently (June 2014) shipping with the F6 BIOS, which means the system acts almost completely dead if you have a Haswell Refresh (e.g. i7-4790) CPU installed. To make things more fun, my motherboard was NOT Qflash enabled, and I certainly don’t have Windows, so my only option was DOS flashing. […]

802.1x wireless WPA2-Enterprise without certificate: Ubuntu 14.04

NetworkManager in Ubuntu 14.04 has an issue with 802.1x networks that don’t require the laptop to have a .cert file. A bug report has been launched in regards to this. Note: the following discussion can subject your laptop to “man-in-the-middle” attacks by disregarding the need for a .cert file. However, if your network IT dept. […]

Matplotlib Python3: fixing pyplot.imshow()

I have noticed on my Ubuntu 14.04 PCs and have seen other OSs having issues with python3 and matplotlib.pyplot.imshow(). Errors like: backend_gtk3cairo.RendererGTK3Cairo … NotImplementedError: Surface.create_for_data: Not Implemented yet. and getting blank images. I fixed the problem by switching the matplotlib backend as follows: 1) placing a file named “matplotlibrc” in the directory of my Python […] Windows client under Wine / Linux

So far, the webcam doesn’t work, but the send/receive audio does work on a test call. I didn’t test receiving video. NOTE: in an actual conference, I wasn’t able to get sound, and so had to use a telephone. I have also seen problems with this for people using Windows and Mac at a large […]