Setting a blank desktop background in Gnome

Posted on Wed 29 April 2020 in IT • Tagged with linux, ubuntu, gnome

I've just upgraded to Ubuntu 20.04, and there's no obvious way in the settings to get rid of desktop wallpaper, if all you want is a plain background. There's a quick way at the command-line though:

gsettings set org.gnome.desktop.background picture-uri none
gsettings set org.gnome.desktop …

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Using a Raspberry Pi as a lightweight JetDirect interface

Posted on Thu 23 April 2020 in IT • Tagged with linux, networks, printing

At home I've got a B&W LaserJet 1160, probably from around 2006-ish, that's not networked. I've also got a first-generation Raspberry Pi running Pi-hole. The Pi doesn't have enough RAM to also handle print jobs and prepare them for the printer, but it is able to be a super-simple …

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Unicode flags

Posted on Mon 06 August 2018 in IT • Tagged with unicode

Unicode, despite having room for it, does not have a table of national flags. Instead they created a set of 26 "Regional Indicators", from U+1F1E6 ('REGIONAL INDICATOR SYMBOL LETTER A') to U+1F1FF ('REGIONAL INDICATOR SYMBOL LETTER Z') (See the "Enclosed Alphanumeric Supplement" code chart). Putting two of these …

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TDD saved me and I didn't realise it

Posted on Sun 12 November 2017 in IT • Tagged with python

U+1F410 GOAT

U+1F410 GOAT

Years ago at PyCon Ireland there was an enthusiastic workshop on Test-Driven Development (TDD) by Harry Percival. (He's written a book on it, now in its second edition). The idea is that you write the tests first, show they fail, then write the minimum of code to …

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Writing from Vim straight into the X clipboard

Posted on Mon 05 December 2016 in IT • Tagged with linux

I use Vim almost exclusively for my text editing. Every now and again I need to get the contents of the file into the clipboard so I can paste it into something, like a browser window maybe. Highlighting with a mouse is fine for occasional use, but if you're doing …

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How to get to old SSLv3 interfaces now that browsers are dropping it?

Posted on Wed 23 September 2015 in IT • Tagged with networks

SSLv3 is broken, and you shouldn't use it any more. However, there's still lots of old hardware with embedded web interfaces that use it, like air conditioners, UPSs and other stuff. Essentially this hardware has been abandoned by their manufacturers, and there's no hope of there being a firmware update …

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Copying LTSP root image on bootup

Posted on Sat 19 September 2015 in IT • Tagged with linux

LTSP logo

In work we use LTSP to boot up thin clients. Nothing runs locally on these thin clients, they're used for either VNC or rdesktop access. One problem we had was that if the LTSP server was rebooted, the NBD client would lose its connection to the server and never re-establish …

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Inflation calculator

Posted on Sun 28 June 2015 in IT • Tagged with javascript

As a first attempt at writing something entirely browser-based, I've made an Inflation calculator. There are, currently, four different indexes to choose from.

It uses AngularJS for the interactive bits, Bootstrap for the layout, and Dygraphs for the graphs.

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"zfs replace" on a dying disk

Posted on Tue 03 February 2015 in IT • Tagged with linux, zfs

For the last day I thought the disks in my home server sounded a bit busy. Usually they're so idle they spin down for much of the day, but they were clicking away when they shouldn't be. Later the same day I got delightful logcheck mails saying things like "I …

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RTNETLINK answers: File exists

Posted on Mon 02 February 2015 in IT • Tagged with linux, networks

While setting up a second bridge for virtual machines on an Ubuntu server, I ended up with this error:

# ifup br1

Waiting for br1 to get ready (MAXWAIT is 3 seconds).
RTNETLINK answers: File exists
Failed to bring up br1.

I found lots of different explanations and possibilities described, but …

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