Using POSIX shell as companion tool — Today I had the need to generate multiple directories at once. In particular the required structure was YYYY-MM. To do so in POSIX shell (for example FreeBSD’s sh) you just do: mkdir `for i in $(seq 1 12); do printf "2012-%02d " $i; done` This simple line will do the…

How to process command line arguments — There are many examples on how to program Motif applications, but sometimes locating certain good practices required to write complete Motif applications is harder. This series is going to focus more on the practical small features that are required to write a complete application. Many applications will require command line…

A basic Hello World example in Motif — Motif was once the UNIX standard widget toolkit. It has been used as the core UNIX GUI library that has built most of the scientific, industrial and mission critical software in the 90s. While its relevance has gone long time ago, it is still used in legacy software and it…

A basic implementation with C99 source code — Data preparation is expected to be 80% of the effort in AI and ML projects. This value comes mainly from the needs for data cleansing but there are also activities related to data normalisation that take a considerable amount of time, especially until the right approach is found. As it…

nroff / troff / pic / eqn / graph — UNIX® was first developed in 1969 by Ken Thompson with the support and ideas from Rudd canaday, Doug McIlroy, Joe Ossanna and Dennis Ritchie. The original team convinced Bell Labs to support and fund the project with the promise of delivering a document management system. That was likely the corporate…

A concise guide to deal with time zones in time series — Whoever has handled timestamps with timezones in time series analysis has always faced some headache. No matter how many times I deal with time series, which in my case invariantly involves dealing with time zones, I always have to revisit how it works because it is often counter-intuitive. The need Working with…

A CSV read performance test among C, Python and C++ — Introduction I tend to feel like a dinosaur when I use C. Nobody knows C anymore. It is no longer mainstream and its usage is mostly related to driver or OS programming and embedded systems. Is it worth learning C anymore? I initially thought that knowing C++ would make C irrelevant…

IPC to simplify medium and large applications development — Introduction Data Science visualisation normally gravitates around displaying individual charts and graphs. Therefore, there is a lot of material covering graphic libraries and frameworks to generate charts. Most advanced charting and plotting libraries allow interaction with data, but…