The Doctor virtadpt

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)

SSH agent forwarding and screen

When connecting to a remote server via SSH it is often convenient to use SSH agent forwarding so that you don't need a separate keypair on that server for connecting to further servers.

This is enabled by adding the

ForwardAgent yes

option to any of your Host entries in ~/.ssh/config (or alternatively with the -A option). Don't set this option in a wildcard Host * section since any user on the remote server that can bypass file permissions can now als use keys loaded in your SSH agent. So only use this with hosts you trust.

Each of these commands will run an ad hoc http static server in your current (or specified) directory, available at http://localhost:8000. Use this power wisely.

Discussion on reddit.

Python 2.x

$ python -m SimpleHTTPServer 8000

This article is now published on my website: Prefer Subshells for Context.

Demagnetizr - Tweetable Magnet URLs

Demo

Donwloadable/tweetable torrent of M.I.A's Piracy Funds Terrorism

The problem

Many web and desktop applications turn a URL in the text you type into a clickable

	#!/bin/sed -rf
	# How to run:
	# echo 'A A<1+B1-C>B<1-A1+B>D<1-B1qC> 0<0>0'
	# Note: Your local sed may use a different flag for "extended" regexes; this is written for GNU sed.
	#
	# tape: [active-state] " " (state-name "<" (write move next-state)_0 (write move next-state)_1 ">")* " " tape... "<" curpos ">" tape...
	# State names can be any character not in " <>".
	# The tape consists of 0's and 1's.
	# The "move" field can be "-" to move left, "+" to move right, or "q" to halt.

	# Install ARCH Linux with encrypted file-system and UEFI
	# The official installation guide (https://wiki.archlinux.org/index.php/Installation_Guide) contains a more verbose description.

	# Download the archiso image from https://www.archlinux.org/
	# Copy to a usb-drive
	dd if=archlinux.img of=/dev/sdX bs=16M && sync # on linux

	# Boot from the usb. If the usb fails to boot, make sure that secure boot is disabled in the BIOS configuration.

	# Set swedish keymap