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justinmklam / python-system-commands.md
Last active June 16, 2021 21:09
Ways to execute shell commands from python using subprocess

Basic example:

import os

os.system("python --version")

Better, since stdout and return codes aren't easily processed when using os.system:

@justinmklam
justinmklam / postgresql.md
Last active September 29, 2022 18:27
Postgresql cheat sheet

Installation

brew install postgres

# Start the service and register to autostart on boot
brew services start postgresql

# Create user
createdb $(whoami)
@justinmklam
justinmklam / progressbar.py
Last active June 4, 2021 15:17
Simple progress bar without external dependencies. Adapted from https://stackoverflow.com/a/34482761
import os
import sys
def progressbar(it, prefix="", file=sys.stdout):
count = len(it)
num_bar_chars = 5
width = os.get_terminal_size().columns - (
len(prefix) + len(str(count)) * 2 + num_bar_chars
)
@justinmklam
justinmklam / mac-os-apps.md
Last active July 8, 2022 21:32
Mac utility apps that make everyday computing easier.

Brew

Install the following with:

# Add --cask if required
brew install $(cat brew-packages.txt)

In brew-packages.txt:

@justinmklam
justinmklam / karabiner-custom-capslock.json
Last active February 27, 2025 09:24
Map caps lock to esc (if tapped) or control (if held down or combined with another key). Use with Karabiner Elements on MacOS
{
"title": "Change caps_lock to Esc and Control",
"rules": [
{
"description": "Post Esc if Caps is tapped, Control if held.",
"manipulators": [
{
"type": "basic",
"from": {
"key_code": "caps_lock",
@justinmklam
justinmklam / docker-cheet-sheet.md
Last active July 12, 2022 19:28
Docker cheat sheet

Building

# Specify tag 
docker build -t mycontainer .

# Specify dockerfile
docker build -f Dockerfile .
@justinmklam
justinmklam / matplotlib-legend-locations.py
Created December 17, 2020 20:22
Matplotlib legend locations. Source: https://stackoverflow.com/a/43439132
# Outside top right
l1 = plt.legend(bbox_to_anchor=(1.04,1), borderaxespad=0)
# Outside bottom right
l2 = plt.legend(bbox_to_anchor=(1.04,0), loc="lower left", borderaxespad=0)
# Outside center right
l3 = plt.legend(bbox_to_anchor=(1.04,0.5), loc="center left", borderaxespad=0)
# Outside top single row
l4 = plt.legend(bbox_to_anchor=(0,1.02,1,0.2), loc="lower left",
mode="expand", borderaxespad=0, ncol=3)
# Outside bottom right
@justinmklam
justinmklam / mlx90640.py
Created December 11, 2020 19:50
Sample code to show real-time thermal camera images with the MLX90640 on a Raspberry Pi. Sample rate is ~0.6 fps.
##########################################
# MLX90640 Thermal Camera w Raspberry Pi
# -- 2Hz Sampling with Simple Routine
##########################################
#
import time,board,busio
import numpy as np
import adafruit_mlx90640
import matplotlib.pyplot as plt
@justinmklam
justinmklam / linux-export-all-env-variables.sh
Created December 2, 2020 05:55
Export a file of env variables. Source: https://unix.stackexchange.com/a/79077
## Option 1
# Set all variables to be automatically exported
set -a
# '.' is the standard way to source variables. 'source' is available in most Bourne shells
. .env
# Disable automatic export
set +a
# Option 2 (for POSIX shells)
set -o allexport
@justinmklam
justinmklam / linux-email-ssmtp-configuration.md
Created August 26, 2020 22:11
Set up email from a linux server