zuigon

Let's say you have a Bash shell script, and you need to run a series of operations on another system (such as via ssh). There are a couple of ways to do this.

First, you can stage a child script on the remote system, then call it, passing along appropriate parameters. The problem with this is you will need to manually keep the remote script updated whenever you change it -- could be a bit of a challenge when you have something to execute on a number of remote servers (i.e., you have a backup script running on a central host, and it needs to put remote databases in hot backup mode before backing them up).

Another option is to embed the commands you want to run remotely within the ssh command line. But then you run into issues with escaping special characters, quoting, etc. This is ok if you only have a couple commands to run, but if it is a complex piece of Bash code, it can get a bit unwieldy.

So, to solve this, you can use a technique called rpcsh -- rpc in shell script, as follows:

First, place th

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)

Installation

pacman -S mpd ncmpcpp

MPD

copy the example configuration in mpd.conf

# cp /usr/share/doc/mpd/mpdconf.example /etc/mpd.conf

An Ansible summary

Jon Warbrick, July 2014, V3.2 (for Ansible 1.7)

Configuration file

intro_configuration.html

First one found from of

	# vim: set softtabstop=2 tabstop=2 shiftwidth=2 expandtab autoindent syntax=nix nocompatible :
	# Containers

	{ config, pkgs, ... }:

	{ containers.browser =
	let hostAddr = "192.168.100.10";
	in
	{ privateNetwork = true;
	hostAddress = hostAddr;

	* {
	font-size: 12pt;
	font-family: monospace;
	font-weight: normal;
	font-style: normal;
	text-decoration: none;
	color: black;
	cursor: default;
	}

	/* bling.js */
	window.$ = document.querySelector.bind(document);
	window.$$ = document.querySelectorAll.bind(document);
	Node.prototype.on = window.on = function(name, fn) { this.addEventListener(name, fn); };
	NodeList.prototype.__proto__ = Array.prototype;
	NodeList.prototype.on = function(name, fn) { this.forEach((elem) => elem.on(name, fn)); };

	# do it once
	seq 1 \| parallel -n0 "curl -H 'Content-Type: application/json' http://httpbin.org/post -X POST -d '{\"url\":\"http://google.com/\"}'"

	# do it twice
	seq 2 \| parallel -n0 "curl -H 'Content-Type: application/json' http://httpbin.org/post -X POST -d '{\"url\":\"http://google.com/\"}'"

	# do it 4 times, but at 2 a time
	seq 4 \| parallel -n0 -j2 "curl -H 'Content-Type: application/json' http://httpbin.org/post -X POST -d '{\"url\":\"http://google.com/\"}'"

	# you can also put all your commands into a file

	require 'socket'
	require 'openssl'
	require 'puma/server'
	require 'ds9'

	class Server < DS9::Server
	def initialize socket, app
	@app = app
	@read_streams = {}
	@write_streams = {}

	#!/usr/local/bin/fontforge
	# Usage: fontforge -script ttc2ttf.pe /path/to/font.ttc

	fonts = FontsInFile($1)
	n = SizeOf(fonts)
	i = 0
	while (i < n)
	Open($1 + "(" + fonts[i] + ")", 1)

	index = ToString(i + 1)