Vassil Kalkov kalkov

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

Capybara

save_and_open_page

Matchers

have_button(locator)

PSQL

Magic words:

psql -U postgres

Some interesting flags (to see all, use -h):

-E: will describe the underlaying queries of the \ commands (cool for learning!)
-l: psql will list all databases and then exit (useful if the user you connect with doesn't has a default database, like at AWS RDS)

Headless Ethminer (nVidia) Setup Guide

Cian Johnston, July 2017

A couple of weeks ago, I decided I should put my gaming rig to work crypto mining. I did not expect to make any significant profit on this, it was more of a fun project to set up. However, there were a large number of tutorials and guides already out there, and many were more than a year out of date.

This guide assumes the reader already has a crypto wallet set up, is comfortable with Linux and the command line, and knows how to use Google if they run into problems.

The end result is an Ubuntu 16.04 LTS headless server running CUDA ethminer via systemd.

Hardware

Common Options

-#, --progress-bar Make curl display a simple progress bar instead of the more informational standard meter.

-b, --cookie <name=data> Supply cookie with request. If no =, then specifies the cookie file to use (see -c).

-c, --cookie-jar <file name> File to save response cookies to.

How to install virtualenv:

Install pip first

sudo apt-get install python3-pip

Then install virtualenv using pip3

sudo pip3 install virtualenv

Utilities you'll care about

All these are already installed on epyc.

kafkacat (conda install -c conda-forge kafkacat)
kt (grab it from https://github.com/fgeller/kt/releases)
kafka-* (come with kafka, if you yum install if from Confluent's repo, or via Docker if you're so inclined). Warning -- JVM based and dreadfully slow.
jq (conda install -c conda-forge jq or use your favorite package manager)

	# ------------------------------------------------------------------------------
	# 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.

	const data = msg.payload

	const voltage = data[0]*0.1
	const current = data[1]*0.1
	const phase = data[2]*0.1
	const power = data[3]
	const power_reactive = data[4]
	const power_apparent = data[5]
	const power_efficiency = data[6]*0.1
	const total_power = (data[7] * (1 << 16) + data[8]) / 100