Justin Lam justinmklam

Some days you're the dog, other days you're the hydrant.

justinmklam / kill-subprocess-group-demo.py

Last active March 8, 2019 17:50

Example code to launch a subprocess and terminate all spawned/child processes. For use when .kill() and .terminate() don't work.

	# Source: https://stackoverflow.com/a/4791612

	import os
	import signal
	import subprocess

	# The os.setsid() is passed in the argument preexec_fn so
	# it's run after the fork() and before exec() to run the shell.
	pro = subprocess.Popen(cmd, stdout=subprocess.PIPE,
	shell=True, preexec_fn=os.setsid)

justinmklam / enable-arduino-upload-linux.sh

Created March 9, 2019 19:37

Change serial port permissions for Arduino to enable sketch upload.

	# Error:
	# Loading configuration...
	# Initializing packages...
	# Preparing boards...
	# Verifying...
	# Sketch uses 4044 bytes (12%) of program storage space. Maximum is 32256 bytes.
	# Global variables use 407 bytes (19%) of dynamic memory, leaving 1641 bytes for local variables. Maximum is 2048 bytes.
	# Uploading...
	# An error occurred while uploading the sketch
	# avrdude: ser_open(): can't open device "/dev/ttyACM0": Permission denied

justinmklam / common-shebangs.md

Last active September 20, 2019 18:03

Common shebangs for shell scripts.

For POSIX (ie. not just Linux):

#!/bin/sh.

For GNU bash:

justinmklam / linux-colours-in-bash-script.sh

Created March 21, 2019 23:17

Simple demo for adding terminal colours to a bash script.

	#!/usr/bin/env bash

	# Colours for terminal colours
	RED=`tput setaf 1`
	GREEN=`tput setaf 2`
	YELLOW=`tput setaf 3`
	PINK=`tput setaf 5`
	CYAN=`tput setaf 6`
	RESET=`tput sgr0`

justinmklam / i3-setup.sh

Last active March 29, 2019 16:15

Handy commands to modify i3

	# Add latest repo to ubuntu
	/usr/lib/apt/apt-helper download-file http://debian.sur5r.net/i3/pool/main/s/sur5r-keyring/sur5r-keyring_2019.02.01_all.deb keyring.deb SHA256:176af52de1a976f103f9809920d80d02411ac5e763f695327de9fa6aff23f416
	dpkg -i ./keyring.deb
	echo "deb http://debian.sur5r.net/i3/ $(grep '^DISTRIB_CODENAME=' /etc/lsb-release \| cut -f2 -d=) universe" >> /etc/apt/sources.list.d/sur5r-i3.list
	apt update
	apt install i3

	# Copy config to home directory. Modify ctrl+grave
	mkdir ~/.config/dunst
	cp /etc/xdg/dunst/dunstrc ~/.config/dunst/dunstrc

justinmklam / write-32bit-to-8bit-eeprom.c

Last active April 9, 2019 18:31

Reference for bit shifting 32 bit to 8 bit and vice versa.

	#include <EEPROM.h>

	void EEPROMWrite32bit(uint8_t address, uint32_t value)
	{
	uint8_t bytes[4];

	bytes[0] = (value >> 24) & 0xFF;
	bytes[1] = (value >> 16) & 0xFF;
	bytes[2] = (value >> 8) & 0xFF;
	bytes[3] = value & 0xFF;

justinmklam / setup-ssh-keys.md

Last active November 20, 2019 00:59

Setup SSH keys

cd ~/.ssh

mkdir key_backup
cp id_rsa* key_backup

justinmklam / android-studio.gitignore

Created April 16, 2019 00:34

Minimal gitignore for Android Studio project.

	# Gradle files
	.gradle/
	build/

	# Local configuration file (sdk path, etc)
	local.properties

	# IntelliJ
	*.iml
	.idea/workspace.xml

justinmklam / linux-ubuntu-install-nvidia.sh

Created April 17, 2019 21:34

Install nvidia drivers in Ubuntu 16.04

	# Check current driver
	sudo lshw -C display

	# Check available drivers. Example output:
	# == /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0 ==
	# modalias : pci:v000010DEd000013B0sv00001462sd0000116Bbc03sc02i00
	# vendor : NVIDIA Corporation
	# model : GM107GLM [Quadro M2000M]
	# driver : nvidia-384 - distro non-free recommended
	# driver : xserver-xorg-video-nouveau - distro free builtin

justinmklam / bitwise-operations.c

Last active April 26, 2019 23:08

Cheat sheet for bitwise operations

	// Set certain bits without affecting the rest.
	// Clear all bits to a known value, then set them.
	// newvalue must contain all bits
	value = (value & ~mask) \| (newvalue & mask);