dvliman

$: (Dollar Colon) is basically a shorthand version of $LOAD_PATH. $: contains an array of paths that your script will search through when using require.
$0 (Dollar Zero) contains the name of the ruby program being run. This is typically the script name.
$* (Dollar Splat) is basically shorthand for ARGV. $* contains the command line arguments that were passed to the script.
$? (Dollar Question Mark) returns the exit status of the last child process to finish.
$$ (Dollar Dollar) returns the process number of the program currently being ran.
$~ (Dollar Tilde) contains the MatchData from the previous successful pattern match.
$1, $2, $3, $4 etc represent the content of the previous successful pattern match.
$& (Dollar Ampersand) contains the matched string from the previous successful pattern match.
$+ (Dollar Plus) contains the last match from the previous successful pattern match.
$` (Dollar Backtick) contains the string before the actual matched string of the previous successful pattern match.

jessejanderson

Community

• Elixir Slack Group

Cheatsheets

• GenServer Cheatsheet by Benjamin Tan Wei Hao

Books

enzinier

#!/bin/sh
# Userland mode (~$USER/), (~/).

# ~/.fonts is now deprecated and that
#FONT_HOME=~/.fonts
# ~/.local/share/fonts should be used instead
FONT_HOME=~/.local/share/fonts

echo "installing fonts at $PWD to $FONT_HOME"
mkdir -p "$FONT_HOME/adobe-fonts/source-code-pro"

wilon

普通模式

	命令	说明 + 示例
	ds	删除括号
例	ds "	"Hello world!" => Hello world!
	cs	替换括号
例	cs "(	"Hello world!" => (Hello world!)
	cS	替换括号，括号内文本做新一行
例	cS "{	"Hello world!" => {     Hello world! }

stevencch99

function primeString(s, count = 1) {
  // 如果字串中有重複的模式，最少也會重複 1 次，故迭代超過字串長度的一半還沒找到就不用找了
  if(count > s.length / 2) { return true }
  
  // 每次迭代將字串的一小塊，設定為分割陣列的符號 chunk
  let chunk = s.slice(0, count)
  // 被 chunk 切過的部分會變成陣列中的空元素，此行判斷是不是能夠將陣列切成重複的小塊
  // 如果切完後全部的陣列元素都是空的，代表字串被 chunk 整除，恭喜找到規律。
  let grouped = s.split(chunk).every(i => i === '')
  

stevencch99

#!/bin/sh
# Userland mode (~$USER/), (~/).

# ~/.fonts is now deprecated and that
#FONT_HOME=~/.fonts
# ~/.local/share/fonts should be used instead
FONT_HOME=~/.local/share/fonts

echo "installing fonts at $PWD to $FONT_HOME"
mkdir -p "$FONT_HOME/adobe-fonts/source-code-pro"

PJUllrich

Big-O Time Complexities for Elixir data structures

Map [1]

Operation	Time Complexity
Access	O(log n)
Search	O(log n)
Insertion	O(n) for <= 32 elements, O(log n) for > 32 elements [2]
Deletion	O(n) for <= 32 elements, O(log n) for > 32 elements

karpathy

LLM Wiki

A pattern for building personal knowledge bases using LLMs.

This is an idea file, it is designed to be copy pasted to your own LLM Agent (e.g. OpenAI Codex, Claude Code, OpenCode / Pi, or etc.). Its goal is to communicate the high level idea, but your agent will build out the specifics in collaboration with you.

The core idea

Most people's experience with LLMs and documents looks like RAG: you upload a collection of files, the LLM retrieves relevant chunks at query time, and generates an answer. This works, but the LLM is rediscovering knowledge from scratch on every question. There's no accumulation. Ask a subtle question that requires synthesizing five documents, and the LLM has to find and piece together the relevant fragments every time. Nothing is built up. NotebookLM, ChatGPT file uploads, and most RAG systems work this way.