Posted by Michał ‘mina86’ Nazarewicz on 1st of September 2016
Python! My old nemesis, we meet again. Actually, we meet all the time, but despite that there are always things which I cannot quite remember how to do and need to look them up. To help with the searching, here there are collected in one post:
Some regular visitors of the web site may be aware that the page used to run on Jogger.pl platform. Some will also be aware that the service closes shop, an act which forced me to move to another hosting.
In moving the page, I’ve tried to keep old URLs work so even though canonical locations for posts have changed, the old links should result in a correct redirect.
This is also true for feeds but while Jogger provided customisation options (RSS and Atom, excerpts only, no HTML and posts count), currently only full-content HTML Atom feeds limited to newest ten entries are provided.
If anything broke for you, please do let me know at mina86@mina86.com.
I have not yet figured out what to do with comments which is why commenting is currently unavailable. Since I want my whole page to be completely static, I’m planning on using a third-party widget. So far I’ve narrowed the choice down to HTML Comment Box and the new hotness, Spot.IM. Any suggestions are also welcome.
On the bright side, the page now loads five times faster! Jogger.pl took its sweet time when generating responses. A static page and better optimised infrastructure of my current provider allows to drop response time from 300 to 60 ms.
Posted by Michał ‘mina86’ Nazarewicz on 25th of October 2015
There are a lot of misconceptions about Unicode. Most are there because people assume what they know about ASCII or ISO-8859-* is true about Unicode. They are usually harmless but they tend to creep into minds of people who work with text which leads to badly designed software and technical decisions made based on false information.
Without further ado, here’s a few facts about Unicode that might surprise you.
Posted by Michał ‘mina86’ Nazarewicz on 28th of September 2015
There are multiple ways to customise Bash prompt. There’s no need to look for long to find plethora of examples with fancy, colourful PS1s. What have been a bit problematic is having text on the right of the input line. In this article I’ll try to address that shortcoming.
Getting text on the right
The typical approach is using PROMPT_COMMAND to output desired content. The variable specifies a shell code Bash executes prior to rendering the primary prompt (i.e. PS1).
The idea is to align text to the right and then using carrier return move the cursor back to the beginning of the line where Bash will start rendering its prompt. Let’s look at an example of showing time in various locations:
__command_rprompt() {
local times= n=$COLUMNS tz
for tz in ZRH:Europe/Zurich PIT:US/Eastern \
MTV:US/Pacific TOK:Asia/Tokyo; do
[ $n -gt 40 ] || break
times="$times ${tz%%:*}\e[30;1m:\e[0;36;1m"
times="$times$(TZ=${tz#*:} date +%H:%M)\e[0m"
n=$(( $n - 10 ))
done
[ -z "$times" ] || printf "%${n}s$times\\r" ''
}
PROMPT_COMMAND=__command_rprompt
Clearing the line on execution
It has one annoying issue. The right text reminds on screen even after executing a command. Typically this is a matter of aesthetic but it also makes copying and pasting session history more convoluted.
A manual solution is to use redraw-current-line readline function (e.g. often bound to C-l). It clears the line and prints the prompt and whatever input has been entered thus far. PROMPT_COMMAND is not executed so the right text does not reappear.
Lack of automation can be addressed with a tiny bit of readline magic and a ~/.inputrc file which deserves much more fame than what it usually gets.
Tricky part is bindind C-m and C-j to two readline functions, redraw-current-line followed by accept-line, which is normally not possible. This limitation can be overcome by binding the key sequences to a different sequence which will be interpreted recursively.
A few days ago I received an email from Google Wembaster Tools saying no more no less but: ‘Your webpage sucks on mobile devices!’ Or something. Now that I think of it, I could have been worded slightly differently. The gist was the same though.
I never paid that much attention to how my site looks on phones and tables. I’ve made sure it loaded and looked, but apart from that never spent much time on the issue. I always thought optimising for a small screen would be a lengthy and painful process. How mistaken I was!
In my defence, when I last looked at the problem, state of mobile browsers was different; now there are two things to do. First, add a viewport meta tag, e.g.:
and then use min-width or max-width CSS media queries. Admittedly the second part may take some time, but if your layout uses simple markup rather than being TABLE-based, reading the excellent article on A List Apart might turn out to be the most time consuming step.
If you haven’t already, do take a look at whether your website looks reasonably well on small screens. Apparently mobile is the future, or some such.
The ‘bad’ news is that I’ve dropped endless scroll feature. This is because in narrow layout the sidebar moves to the bottom and endless scrolling would make it unreachable since it would run away all the time.
Posted by Michał ‘mina86’ Nazarewicz on 11th of March 2015
For people who know me it should come with no surprise that I support free software in most forms it can take. I also believe that if someone gives you something at zero price, basic courtesy dictates that you follow wishes of that person. This is why when Software Freedom Conservancy started a GPL Compliance Project for Linux Developers I didn’t hesitate even for a minute to offer little Linux copyright I held to help the effort.
Most importantly though, it is why I fully support Conservancy in taking legal action against VMware which for years has been out of compliance with Linux’s license.
If you care about free software, the GPL or want more projects like OpenWrt, consider donating to help Christoph Hellwig and the Conservancy with their legal battle against this multi-billion-dollar corporation who for some reason decided to free-ride on other people’s work without respecting their wishes.
If you can’t or don’t want to donate, twitting something along the lines of ‘Play by the rules, @VMware. I defend the #GPL with Christoph & @Conservancy. #DTRTvmware Help at https://sfconservancy.org/supporter/’ or otherwise spreading the word will help as well. Oh, and in case you were, like I was, wondering — DTRT stands for ‘do the right thing’.
Posted by Michał ‘mina86’ Nazarewicz on 14th of December 2014
Don’t you hate when you need to do something you had done before, but cannot remember how exactly? I’ve been in that situation several times and sometimes looking up for a correct method turned out considerably harder than it should. To alleviate the need for future Googling, here’s a bag of notes I can reference easily:
Posted by Michał ‘mina86’ Nazarewicz on 18th of May 2014
Outside of functional programming context, map-reduce refers to a technique for processing data. Thanks to properties of map and reduce operations, computations which can be expressed using them can be highly parallelised, which allows for faster processing of high volumes of data.
If you’ve ever wondered how tools such as Apache Hadoop work, you’re at the right page. In this article I’ll explain what map and reduce are and later also introduce a shuffle phase.
Posted by Michał ‘mina86’ Nazarewicz on 25th of January 2014
Same as my previous article written in Polish, this text will describe some steps I take after installing Slackware Linux. I try to strike a balance between performance, security and usability, but not everything written here may work for everyone. You have been warned.