LaSombra lasombra

Turn auto-exposure off, set absolute exposure to a low level and use gain to compensate for low light if needed. E.g.:

v4l2-ctl -d /dev/video2 -c exposure_absolute=400
v4l2-ctl -d /dev/video2 -c gain=110

# check with
v4l2-ctl -d /dev/video2 -L

How to mount a qcow2 disk image

This is a quick guide to mounting a qcow2 disk images on your host server. This is useful to reset passwords, edit files, or recover something without the virtual machine running.

Step 1 - Enable NBD on the Host

modprobe nbd max_part=8

Disable Device Enrollment Program (DEP) notification on macOS Catalina.md

With full reinstall (recommended)

a. Boot into recovery using command-R during reboot, wipe the harddrive using Disk Utility, and select reinstall macOS

b. Initial installation will run for approximately 1 hour, and reboot once

c. It will then show a remaining time of about 10-15 minutes

Quick Tips for Fast Code on the JVM

I was talking to a coworker recently about general techniques that almost always form the core of any effort to write very fast, down-to-the-metal hot path code on the JVM, and they pointed out that there really isn't a particularly good place to go for this information. It occurred to me that, really, I had more or less picked up all of it by word of mouth and experience, and there just aren't any good reference sources on the topic. So… here's my word of mouth.

This is by no means a comprehensive gist. It's also important to understand that the techniques that I outline in here are not 100% absolute either. Performance on the JVM is an incredibly complicated subject, and while there are rules that almost always hold true, the "almost" remains very salient. Also, for many or even most applications, there will be other techniques that I'm not mentioning which will have a greater impact. JMH, Java Flight Recorder, and a good profiler are your very best friend! Mea

Git Cheat Sheet

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Commands

Getting Started

git init

or

	#!/usr/bin/env python3
	# This script is useful for setting fallback mtime for isync/mbsync CopyArrivalDate option
	# If you use notmuch then you could do something like this to fix mtime on new mail
	# notmuch search --output=files tag:new \| xargs -P0 -i ~/code/mailutils/fix_maildir_mtime.py {}

	import email
	import sys
	import os
	from email.utils import parsedate_tz, mktime_tz

	%global namedreltag .Final
	%global namedversion %{version}%{?namedreltag}
	%global majorversion 6
	Name: hibernate-validator
	Version: 6.0.17
	Release: 1%{?dist}
	Summary: Bean Validation 2.0 (JSR 380) Reference Implementation
	License: ASL 2.0
	URL: https://hibernate.org/validator/
	Source0: https://github.com/hibernate/hibernate-validator/archive/%{namedversion}/%{name}-%{namedversion}.tar.gz

	# ------------------------------------------------------------------------------
	# tlp - Parameters for power saving
	# See full explanation: http://linrunner.de/en/tlp/docs/tlp-configuration.html

	# dir: /etc/default/tlp

	# Hint: some features are disabled by default, remove the leading # to enable
	# them.

	# Set to 0 to disable, 1 to enable TLP.

	import org.slf4j.Logger;
	import org.slf4j.LoggerFactory;

	import java.io.IOException;
	import java.nio.file.*;

	public class FileWatcher {
	private static final Logger log = LoggerFactory.getLogger(FileWatcher.class);

	private Thread thread;

	#!/bin/bash

	# export DBUS_SESSION_BUS_ADDRESS environment variable because cron hates me
	PID=$(pgrep -u USER gnome-session-b)
	export DBUS_SESSION_BUS_ADDRESS=$(grep -z DBUS_SESSION_BUS_ADDRESS /proc/$PID/environ\|cut -d= -f2-)

	/usr/bin/gsettings set org.gnome.shell.extensions.user-theme name 'Flat-Plat'
	/usr/bin/gsettings set org.gnome.desktop.interface gtk-theme 'Flat-Plat'
	/usr/bin/gsettings set org.gnome.desktop.background picture-uri 'file://WALLPAPER-PATH'
	/usr/bin/gsettings --schemadir ~/.local/share/gnome-shell/extensions/[email protected] set org.zzrough.gs-extensions.drop-down-terminal background-color 'rgb(69,90,100)'