Frank Zegarra frankzzz

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

Sample service script for debianoids

Look at LSB init scripts for more information.

Usage

Copy to /etc/init.d:

# replace "$YOUR_SERVICE_NAME" with your service's name (whenever it's not enough obvious)

PSQL

Magic words:

psql -U postgres

Some interesting flags (to see all, use -h or --help depending on your psql version):

-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)

Installing Python 2.7 on Centos 6.5

Centos 6.* comes with Python 2.6, but we can't just replace it with v2.7 because it's used by the OS internally (apparently) so you will need to install v2.7 (or 3.x, for that matter) along with it. Fortunately, CentOS made this quite painless with their Software Collections Repository

sudo yum update # update yum
sudo yum install centos-release-scl # install SCL 
sudo yum install python27 # install Python 2.7

To use it, you essentially spawn another shell (or script) while enabling the newer version of Python:

	#!/bin/bash
	echo "*****************************************"
	echo " Based on information from Google"
	echo " http://dev.chromium.org/spdy/spdy-best-practices"
	echo "*****************************************"
	sudo su
	yum –y update
	echo "*****************************************"
	echo " Changing initcwnd and initrwnd"
	echo " Step 1: check route settings."

	-- Index hit rate
	WITH idx_hit_rate as (
	SELECT
	relname as table_name,
	n_live_tup,
	round(100.0 * idx_scan / (seq_scan + idx_scan + 0.000001),2) as idx_hit_rate
	FROM pg_stat_user_tables
	ORDER BY n_live_tup DESC
	),

	#!/bin/bash
	#
	# Bash script to setup headless Selenium (uses Xvfb and Chrome)
	# (Tested on Ubuntu 12.04) trying on ubuntu server 14.04

	# Add Google Chrome's repo to sources.list
	echo "deb http://dl.google.com/linux/chrome/deb/ stable main" \| sudo tee -a /etc/apt/sources.list

	# Install Google's public key used for signing packages (e.g. Chrome)
	# (Source: http://www.google.com/linuxrepositories/)

	# to generate your dhparam.pem file, run in the terminal
	openssl dhparam -out /etc/nginx/ssl/dhparam.pem 2048