Prototype-X

TL;DR

Install Postgres 9.6, and then:

sudo pg_dropcluster 9.6 main --stop
sudo pg_upgradecluster 9.5 main
sudo pg_dropcluster 9.5 main

Set db path for pg_upgradecluster:

Prototype-X

#!/bin/bash

while :
do
  echo "$(date) @ $(hostname)"
  echo "Performing new stress testing cycle..."
  stress --cpu 20 --io 20 --vm 6 --vm-bytes 25M --timeout 120s 
  cpu=$(</sys/class/thermal/thermal_zone0/temp)
  echo "-------------------------------------------"
  echo "GPU => $(/opt/vc/bin/vcgencmd measure_temp)"

Prototype-X

#!/bin/bash
# cpustatus
#
# Prints the current state of the CPU like temperature, voltage and speed.
# The temperature is reported in degrees Celsius (C) while
# the CPU speed is calculated in megahertz (MHz).

function convert_to_MHz {
    let value=$1/1000
    echo "$value"

Prototype-X

README

Timers provided by systemd can be used as cronjob replacements. More at man systemd.timer.

Suppose we want to periodically trigger cleanup tasks for a baz utility. We 'll create a baz-cleanup.service which will be triggered by a baz-cleanup.timer.

Define the target service unit

Create a minimal service at /lib/systemd/system/baz-cleanup.service:

Prototype-X

#!/usr/bin/env python

"""
rdns.py

This is a Python script that helps you create
reverse DNS zone files for the Bind Name Server.

I published it together with this blog post: http://goo.gl/CJwly .
"""

Prototype-X

#!/bin/bash
#####################################################
# Name: Bash CheatSheet for Mac OSX
# 
# A little overlook of the Bash basics
#
# Usage:
#
# Author: J. Le Coupanec
# Date: 2014/11/04

Prototype-X

PSQL

Magic words:

psql -U postgres

If run with -E flag, it will describe the underlaying queries of the \ commands (cool for learning!).

Most \d commands support additional param of __schema__.name__ and accept wildcards like *.*

Prototype-X

tmux vs. screen commands

---

Action	tmux	screen
start a new session	tmux tmux new tmux new-session	screen
start a new session with a name	tmux new -s name	screen -S name
re-attach a detached session	tmux attach tmux attach-session	screen -r
re-attach a detached session with a name	tmux attach -t name tmux a -t name	screen -r name
re-attach an attached session (detaching it from elsewhere)	tmux attach -dtmux attach-session -d	screen -dr

Prototype-X

000000	Officially Xerox
000001	SuperLAN-2U
000002	BBN (was internal usage only, no longer used)
000003	XEROX CORPORATION
000004	XEROX CORPORATION
000005	XEROX CORPORATION
000006	XEROX CORPORATION
000007	XEROX CORPORATION
000008	XEROX CORPORATION
000009	powerpipes?

Prototype-X

# Monitoring on interface eth0
tcpdump -i eth0 -n port 67 and port 68