hhromic

Slimming Down Raspbian Stretch Lite

Notes for slimming down a fresh installation of Raspbian Stretch Lite. This guide does not strip Raspbian of basic functionality such as Bluetooth and mDNS.

Instructions

Install a fresh Raspbian Stretch Lite image into the SD card ([source][1]).

$ unzip -p 2018-04-18-raspbian-stretch-lite.zip | dd bs=4M of=/dev/sdX conv=fsync

hhromic

#!/usr/bin/env bash
# Show information about IKEA Tradfri devices firmware from the official IKEA servers
# script by github.com/hhromic

# optional filter
declare -r FILTER=$1

# URLs for firmware channels
declare -r -A CHANNEL_URLS=(
  [CURRENT]=http://fw.ota.homesmart.ikea.net/feed/version_info.json

hhromic

Repositories Cloning

BRANCH=master  # or 'rocko'
xargs -n 1 git clone -b $BRANCH <<'__EOF__'
git://git.yoctoproject.org/poky
git://git.openembedded.org/meta-openembedded
git://github.com/agherzan/meta-raspberrypi
git://github.com/webplatformforembedded/meta-wpe
__EOF__

hhromic

Cheat Sheet for Python Time Data

Note: These snippets are tested with Python 3, which has better datetime object support than Python 2.

Textual Time to datetime Object

from datetime import datetime

# example Twitter "created_at" field time format

hhromic

Adafruit PiTFT 2.8" Setup

Last tested on: Raspbian Buster

Setup Display and HDMI

Add the following snippet to /boot/config.txt:

# Adafruit PiTFT 2.8"

dtoverlay=pitft28-resistive,speed=64000000,fps=30

hhromic

Useful LaTeX Snippets

About Lenghts

From https://tex.stackexchange.com/a/16956:

\textwidth is generally the global width of the text area, while \columnwidth is the width of a column of text (it will be different from \textwidth when typesetting in two or more columns). However, inside a minipage, \textwidth will be set to the given argument along with \hsize, \columnwidth, and \linewidth (they will revert to the previous values at the end of the minipage because it forms a group). Note that \parbox doesn't reset \textwidth; the size is available as \linewidth.

The parameter \linewidth contains the line length inside a list (or derived) environment and it may change in a nested list (while \hsize, \textwidth and \columnwidth don't change). >

hhromic

#!/usr/bin/env bash
# Mirror a git repository into another
# script by github.com/hhromic

# origin git repository
declare -r ORIGIN="<<your origin git repository here>>"

# destination git repository (mirror)
declare -r MIRROR="<<your destination (mirror) git repository here>>"

hhromic

Working with Disk Images in Linux

Ref: https://www.linuxquestions.org/questions/linux-general-1/how-to-mount-img-file-882386/#post4365399

To list the partitions of a disk image:

$ fdisk -l mydisk.img
Disk mydisk.img: 15 GiB, 16088301568 bytes, 31422464 sectors
Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

hhromic

Publishing to PyPi

1. Update code
2. Update version number in setup.py or setup.cfg
3. Commit all changes: git commit -a
4. Tag the current state with version number: git tag X.Y.Z
5. Push changes to remote: git push --tags
6. Build source distribution: python setup.py sdist bdist_wheel
7. Release to PyPi: twine upload dist/*
8. Update GitHub release with notes and other stuff

hhromic

#!/usr/bin/env bash
# Show the current capacity of all managed batteries
# script by github.com/hhromic

POWER_SUPPLY_DIR=/sys/class/power_supply
mapfile -t CAPACITIES < <(compgen -G "$POWER_SUPPLY_DIR"/'*'/capacity)

for capacity in "${CAPACITIES[@]}"; do
  battery="${capacity%/*}"
  battery="${battery##*/}"