Mainly using Ada, C(99), Forth, Go, Haskell, Racket, and some Rust for general programming.
AWK, Julia, Python and R for computational science and data analysis.
/bin/sh and Lua for simple scripts and automation.
OpenBSD is the de facto OS in most computers I own. One stray laptop is running The Void (Linux) in case some Windows executable is needed.
Just for fun (and for learning purposes) I also run Plan 9 from Bell Labs.
I am also using an OpenBSD VM from the awesome OpenBSD Amsterdam, which is currently hosting this webpage.
dwm by suckless.org. It is a dynamic window manager which, in my view, ships with pretty sane defaults.
I am using a simple FIFO-based shell script to display information in the status bar.
st by suckless.org, which is one of the most minimal, sane and maintainable terminal emulators.
I am running mksh as interactive shell.
Spleen, a clean, fixed width bitmap font, useful for long work with computers. It also has support for Powerline symbols out of the box.
Mainly using pla, the primitive line alterator.
Previously used vis, for its Plan 9’s structural regular expressions, and nvi because it rocks.
THE STANDARD TEXT EDITOR, and sam are also worthy of some love.
troff. to write most documents.
When typesetting mathematical expressions is needed, LaTeX.
Pandoc, a universal document converter. It is a swiss-army knife program and a live-saver when I have to work with awful formatted docx documents.
This webpage was built using Markdown, lowdown, and a Makefile.
zathura, a free, plugin-based document viewer with vi-like keybindings.
It can open DjVu, EPUB, PDF (via MuPDF, or Poppler), and PostScript.
sxiv, a Simple X Image Viewer. Handles images, animated gifs, has thumbnail and slideshow modes, and allows to run custom scripts. Also reads/writes to standard input/output.
Some good alternatives are feh, imv and meh.
For one-shot tasks, GIMP.
Regarding repetitive tasks, mostly done using custom C code based on farbfeld.
When portability across machones (which I do not have control over) is needed, or while tinkering with new pipelines, ImageMagick (also GraphicsMagick and GMIC.
imscript is also a good resource to understand image processing algorithms.
mblaze with custom scripts.
mpv, a video player which supports a wide variety of video file formats, audio and video codecs, and subtitle types. Also allows directly streaming from web sources using youtube-dl.
A custom build of sent is my preferred presentation software, which creates a presentation from a simple plain text file. For more complex presentations, I use a slightly modified version of the Troff-slider set of macros.
For academic presentations, mostly using Beamer, with a custom minimal template.
sc-im, a ncurses spreadsheet program for terminal.
NetSurf is a neat browser with near-perfect CSS support. Dillo also works great, but has basic CSS support.
The problem with browsing is the current state of the Web. It is beyond broken. In many cases it is impossible to even open a webpage without Javascript.