Lukas lukasjoc

ANSI Escape Sequences

Standard escape codes are prefixed with Escape:

Ctrl-Key: ^[
Octal: \033
Unicode: \u001b
Hexadecimal: \x1B
Decimal: 27

JQ to filter JSON by value

Syntax: cat <filename> | jq -c '.[] | select( .<key> | contains("<value>"))'

Example: To get json record having _id equal 611

cat my.json | jq -c '.[] | select( ._id | contains(611))'

Remember: if JSON value has no double quotes (eg. for numeric) to do not supply in filter i.e. in contains(611)

What forces layout / reflow

All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.

Generally, all APIs that synchronously provide layout metrics will trigger forced reflow / layout. Read on for additional cases and details.

Element APIs

Getting box metrics

elem.offsetLeft, elem.offsetTop, elem.offsetWidth, elem.offsetHeight, elem.offsetParent

C99 List of Undefined Behavior

From N1256: (See http://port70.net/~nsz/c/c99/n1256.html#J.2)

A "shall" or "shall not" requirement that appears outside of a constraint is violated (clause 4).
A nonempty source file does not end in a new-line character which is not immediately preceded by a backslash character or ends in a partial preprocessing token or comment (5.1.1.2).
Token concatenation produces a character sequence matching the syntax of a universal character name (5.1.1.2).
A program in a hosted environment does not define a function named main using one of the specified forms (5.1.2.2.1).
A character not in the basic source character set is encountered in a source file, except in an identifier, a character constant, a string literal, a header name, a comment, or a preprocessing token that is never converted to a token (5.2.1).
An identifier, comment, string literal, character constant, or header name contains an invalid multibyte character or does not

	system.activationScripts.applications.text = let
	env = pkgs.buildEnv {
	name = "system-applications";
	paths = config.environment.systemPackages;
	pathsToLink = "/Applications";
	};
	in
	pkgs.lib.mkForce ''
	# Set up applications.
	echo "setting up /Applications..." >&2

	{-# LANGUAGE TypeSynonymInstances #-}
	data Dual d = D Float d deriving Show
	type Float' = Float

	diff :: (Dual Float' -> Dual Float') -> Float -> Float'
	diff f x = y'
	where D y y' = f (D x 1)

	class VectorSpace v where
	zero :: v

	/*
	* This document is provided to the public domain under the
	* terms of the Creative Commons CC0 public domain license
	*/

	How to boot Arch Linux ARM in QEMU (patched for M1)

	Prerequisites:

	QEMU - patched for M1 processors - patches: https://github.com/utmapp/qemu

	#!/bin/bash -e
	curl -O https://dl.google.com/chrome/mac/stable/GGRO/googlechrome.dmg
	hdiutil attach googlechrome.dmg
	SRC=/Volumes/Google\ Chrome/Google\ Chrome.app/Contents/Frameworks/Google\ Chrome\ Framework.framework/Libraries/WidevineCdm
	DEST=/Applications/Chromium.app/Contents/Frameworks/Chromium\ Framework.framework/Libraries/
	cp -R "$SRC" "$DEST"
	hdiutil detach /Volumes/Google\ Chrome/

	#!/bin/sh

	#From https://golang.org/doc/install/source#environment
	platforms=(aix android darwin dragonfly freebsd illumos js linux netbsd openbsd plan9 solaris windows)
	arches=(386 amd64 arm arm64 mips mipsle mips64 mips64le ppc64 ppc64le s390x wasm)

	#.go file to build
	test "$1" && target="$1"

	if ! test "$target"; then

	# ~/.bashrc: executed by bash(1) for non-login shells.
	# see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)
	# for examples

	# If not running interactively, don't do anything
	[ -z "$PS1" ] && return

	# don't put duplicate lines in the history. See bash(1) for more options
	# ... or force ignoredups and ignorespace
	HISTCONTROL=ignoredups:ignorespace