Pavel Sayekat Pavel-Sayekat

How to resize a qcow2 disk image on Linux

This example takes olddisk.qcow2 and resizes it into newdisk.qcow2, extending one of the guest's partitions to fill the extra space.

1. qcow2 format

1.1. Verify the filesystems of `olddisk.qcow2`

git config --global http.version HTTP/1.1
git config --global http.postBuffer 157286400

Using ADB to control Accessbility settings for easier testing with Android Emulators + Real Devices

It's a lot easier to test accessibility on the fly using ADB. This gist attempts to make the days of navigating through the Android device settings UI to change Accessibility settings obsolete.

These ADB commands will hopefully encourage Android developers to test and use their apps with common Accessiblility settings enabled.

Credit to James Nitsch for inspiring this, and for figuring out the put commands to enable these settings.

Font Scale (Font Size -- Testing Dynamic Text)

Shifting an unprivileged LXC container to privileged

Still experimental...

Assume that the unprivileged container test already exists. We want a privileged container called test2 to have the same rootfs as test.

Create `test2`

Create a privileged container first. Probably need to be the exact same OS as test1!

FFmpeg cheat sheet

A list of useful commands for the FFmpeg command line tool.

Download FFmpeg: https://www.ffmpeg.org/download.html

Full documentation: https://www.ffmpeg.org/ffmpeg.html

Basic conversion

There are a few decent tutorials on how to setup hotspot on Linux, which I will share below, but this tutorial will focus on adversities that you without doubt will face while setting up your AP.

For AP setup we will need:

Hostapd utility
Some dhcp utility
A bit of patience (that was for my case)

How do I know that my WiFi adapter supports AP mode?

In terminal type sudo iw list this command will show info about your wifi interfaces. Look for Supported interface entry, if AP is in it, that means your Wifi devices support hotspot mode.

	#!/usr/bin/env bash
	# castanet.sh: Script to connect a chromecast to a WiFi network.
	#
	# Allows you to put your Chromecast on WiFi and do Chromecast initial setup
	# without using the Google Home app at all, just using a normal Linux computer.
	#
	# You do need your Chromecast to be on Ethernet, or (untested) to join its setup WiFi
	# network with your PC, and you also need to find out its IP yourself with e.g.
	# Wireshark.

	$ modprobe bridge
	$ echo "net.bridge.bridge-nf-call-iptables = 1" >> /etc/sysctl.conf
	$ sysctl -p /etc/sysctl.conf

	sysctl: cannot stat /proc/sys/net/bridge/bridge-nf-call-iptables: No such file or directory sysctl: cannot stat /proc/sys/net/bridge/bridge-nf-call-ip6tables: No such file or directory

	# SOLUTION
	$ modprobe br_netfilter
	$ sysctl -p /etc/sysctl.conf

	# /usr/share/usb_modeswitch/2001:ac01

	# Run manually if required using:
	# usb_modeswitch -v 0x2001 -p 0xac01 -c /usr/share/usb_modeswitch/2001:ac01

	# D-Link DWM-222 A2
	TargetVendor=0x2001
	TargetProduct=0x7e3d
	StandardEject=1

	Notes to make IR shield (made by LinkSprite) work in Raspberry Pi 3 (bought from Amazon [1]).
	The vendor has some documentation [2] but that is not complete and sufficient for Raspbian Stretch.
	Following are the changes that I made to make it work.

	$ sudo apt-get update
	$ sudo apt-get install lirc

	# Add the following lines to /etc/modules file
	lirc_dev
	lirc_rpi gpio_in_pin=18 gpio_out_pin=17