HashNuke

# to undo a git push
git push -f origin HEAD^:master

# to get to previous commit (preserves working tree)
git reset --soft HEAD

# to get back to previous commit (you'll lose working tree)
git reset --hard HEAD^

kentbrew

// early experiments with node had mysterious double requests
// turned out these were for the stoopid favicon
// here's how to short-circuit those requests
// and stop seeing 404 errors in your client console

var http = require('http');

http.createServer(function (q, r) { 

  // control for favicon

emk

-- This is a Hive program. Hive is an SQL-like language that compiles
-- into Hadoop Map/Reduce jobs. It's very popular among analysts at
-- Facebook, because it allows them to query enormous Hadoop data
-- stores using a language much like SQL.

-- Our logs are stored on the Hadoop Distributed File System, in the
-- directory /logs/randomhacks.net/access.  They're ordinary Apache
-- logs in *.gz format.
--
-- We want to pretend that these gzipped log files are a database table,

mshafrir

{
    "AL": "Alabama",
    "AK": "Alaska",
    "AS": "American Samoa",
    "AZ": "Arizona",
    "AR": "Arkansas",
    "CA": "California",
    "CO": "Colorado",
    "CT": "Connecticut",
    "DE": "Delaware",

MohamedAlaa

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

earthgecko

#!/bin/bash
# bash generate random alphanumeric string
#

# bash generate random 32 character alphanumeric string (upper and lowercase) and 
NEW_UUID=$(cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w 32 | head -n 1)

# bash generate random 32 character alphanumeric string (lowercase only)
cat /dev/urandom | tr -dc 'a-z0-9' | fold -w 32 | head -n 1

rgreenjr

-- show running queries (pre 9.2)
SELECT procpid, age(clock_timestamp(), query_start), usename, current_query 
FROM pg_stat_activity 
WHERE current_query != '<IDLE>' AND current_query NOT ILIKE '%pg_stat_activity%' 
ORDER BY query_start desc;

-- show running queries (9.2)
SELECT pid, age(clock_timestamp(), query_start), usename, query 
FROM pg_stat_activity 
WHERE query != '<IDLE>' AND query NOT ILIKE '%pg_stat_activity%' 

ashrithr

Introduction to Kafka

Kafka acts as a kind of write-ahead log (WAL) that records messages to a persistent store (disk) and allows subscribers to read and apply these changes to their own stores in a system appropriate time-frame.

Terminology:

• Producers send messages to brokers
• Consumers read messages from brokers
• Messages are sent to a topic

jwalton

Graphing Widget

The graphing widget shows graphs using the Rickshaw graphing library. The names of data fields should be (vaguely) familiar if you've used Rickshaw before.

It's recommended that you replace the /assets/javascripts/rickshaw.min.js from your dashboard with the latest from here.

Supported HTML data fields

lelandbatey

Description

This simple script will take a picture of a whiteboard and use parts of the ImageMagick library with sane defaults to clean it up tremendously.

The script is here:

#!/bin/bash
convert "$1" -morphology Convolve DoG:15,100,0 -negate -normalize -blur 0x1 -channel RBG -level 60%,91%,0.1 "$2"

Results