Markus Bergholz markuman

This document has moved!

It's now here, in The Programmer's Compendium. The content is the same as before, but being part of the compendium means that it's actively maintained.

Processing JSON using jq

jq is useful to slice, filter, map and transform structured json data.

Installing jq

On Mac OS

brew install jq

All elements are CRLF terminated. CRLF in the examples mean additional CRLFs.

Syntax	Type	null?	empty?	data/value
`+`	Simple string	no	`+`	ASCII string, non-binary safe
`-`	Simple error string	no	`-`	ASCII string, non-binary safe
`:`	Integer	no	no	ASCII-represented 64bit integer
`$(integer)CRLF(data)`	Bulk	`$0CRLF`	`$-1`	Binary safe chunk of bytes
`*(integer)`	Array	`*0`	`*-1`	Array header holding a length/null indicator

Pushing to Multiple Git Repos

If a project has to have multiple git repos (e.g. Bitbucket and Github) then it's better that they remain in sync.

Usually this would involve pushing each branch to each repo in turn, but actually Git allows pushing to multiple repos in one go.

If in doubt about what git is doing when you run these commands, just

date	num_customers	distinct_customers	total_bananas	total_revenue	revenue_per_sale
2016-01-01	345	287	564	3689	6.54
2016-01-02	364	299	582	4080	7.01
...	...	...	...	...	...

Format your storage
Configure networking (it's easiest with LuCI, or just take a look at OpenWRT howtos)
Configure /storage by adding proper options in /etc/config/fstab, or, again, just clicking around in LuCI
opkg update && opkg install tor
Copy proper configuration, namely /etc/tor/torrc and /etc/config/uhttpd
Reboot (or /etc/init.d/uhttpd restart && /etc/init.d/tor restart)
Check /etc/tor/hidden_service/hostname for your public .onion address
...
PROFIT!

	#!/bin/bash

	if [ "$EUID" -ne 0 ]
	then echo "Must be root"
	exit
	fi

	if [[ $# -ne 1 ]];
	then echo "You need to pass a password!"
	echo "Usage:"

	#!/bin/bash
	# Why? Education & zero redis-cli dependecy
	# (it is a shame, however, that this functionality isn't a part of redis-cli... PR on the way)
	HOST=127.0.0.1
	PORT=6379

	if [ $# -lt "2" ]
	then
	echo "Call a Redis command with its last argument being file contents"
	echo "Usage: $0 <Redis command> <keys and arguments for command> <payload>"

	# This file contains key-strings for every of the 16384 slot hashes in Redis Cluster
	# Each line contains the string and a comment with the slot hash
	# Make sure to trim the string so you don't include the whitespace before the # comment
	# Comments start with a hash (#)
	fyimk7v1CgnBo # Slot 0
	8HMdi # Slot 1
	IQhHSeAVHI # Slot 2
	N8mstVwJZoSaIg # Slot 3
	e2esUEU # Slot 4
	Yjj1RFQ5ME # Slot 5

	const I = x => x
	const K = x => y => x
	const A = f => x => f (x)
	const T = x => f => f (x)
	const W = f => x => f (x) (x)
	const C = f => y => x => f (x) (y)
	const B = f => g => x => f (g (x))
	const S = f => g => x => f (x) (g (x))
	const S_ = f => g => x => f (g (x)) (x)
	const S2 = f => g => h => x => f (g (x)) (h (x))