TIL

A repository of TIL, organized by categories, the idea comes from https://github.com/jbranchaud/til, managed with https://github.com/pjambet/til-rb

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Categories

• Ai
• C
• Clojure
• CSS
• Emacs
• Git
• Haskell
• Html
• Hugo
• JavaScript
• macOS
• Misc
• Rails
• Redis
• Ruby
• Sql
• Tmux
• Unix
• Vim
• Zsh

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Ai

• Newlines in pi

C

• Bit fields
• malloc vs calloc
• malloc doesn't necessarily allocate the exact number of bytes you ask for
• Flexible array member

Clojure

• zips
• The "thread" arrow operator

CSS

• SVG Stroke & Fill properties
• How to style hr elements in CSS
• Test test
• Set the background color

Data structures

• Skiplists - a probabilistic data structure

Emacs

• Set the current buffer to read-only
• Set fill-column for git commit
• Removing/Altering Key Bindings from Minor Mode Keymaps
• Disable ruby-rubocop when editing code blocks
• Write texts as if it was formatted as paragraphs
• Use aspell with emacs to spell check a buffer
• Insert current date/timestamp
• Run doom env after making changes to your env
• Navigating with ivy and show previews
• Open a repo in a browser from Magit

F#

• A function returning another function

Git

• hunk format
• Git Revision Format
• Revision format, Ancestry references, and merge commits
• git pull is like git fetch and git merge
• Bring back a deleted file
• Creating a branch alias with git
• Rebase a stack of commits without dealing with conflicts

Hugo

• GitInfo settings

Haskell

• Monads

macOS

• Using two homebrew directories
• SIGINFO (Ctrl -T)

Html

• Use titles
• There is a <ruby> html tag and it has nothing to do with the programming language

Rails

• The difference between preload and includes
• Active Record instances can be initialized through where
• Use scoping to apply a scope to a block
• ActiveJob.perform_now doesn't run execute callback

Redis

• Why there's no ZDIFF[STORE] command(s) (for now)

Misc

• Shortcut for modulo of a power of two
• A simple Hash function
• Multiplying by power of twos and bit shifts
• Create and share beautiful images of your source code
• Adding man pages to an ubuntu box running through Vagrant
• Gnu Units is a thing! (and it's cool)
• SSH Escape Sequences
• Using a config file for ripgrep (rg)
• Release a port immediately
• piping output creates a new process
• The cut command
• UTF8 encoding

Sql

• Count multiple things in a single sql query

Tmux

• Restore C-k after installing vim-tmux-navigator

JavaScript

• Automatically add anchors

Ruby

• Use StringScanner to ... scan strings
• Ruby 2.7 adds Enumerable#filter_map
• Build a fixed size array from scratch
• Print a number as binary
• Forcing integer overflow
• The then method
• Keep the program running but exit pry for now
• Measure elapsed time the right way
• require active support from irb
• Using TIOCGWINSZ

Unix

• less environment variables
• List files in a directory
• Carriage Return resets the cursor position
• Move cursor when priting to terminal
• Get a calendar from the command line
• Navigate to the last location with -
• Count words for all files in a folder
• select(2) semantics with multiple events
• SIGSTOP & SIGCONT
• The path_helper utility initializes the path variable
• Prevent Ctrl-D from accidentally killing a shell
• ls -F includes the trailing slash after directory names (and more)

Vim

• Format a paragraph
• You can quit vim with ZZ
• Count the number of selected lines

Zsh

• For loops!
• pushd & popd
• Profile zsh startup time