jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

pdeschen

#!/bin/sh
#
# <%=@service%>    This shell script takes care of starting and stopping
#                  the <%=@service%> service.
#
# chkconfig: 2345 65 35
# description: <%=@description%> 
#

SERVICE=<%=@service%>

sindresorhus

#!/usr/bin/env bash
# MIT © Sindre Sorhus - sindresorhus.com

# git hook to run a command after `git pull` if a specified file was changed
# Run `chmod +x post-merge` to make it executable then put it into `.git/hooks/`.

changed_files="$(git diff-tree -r --name-only --no-commit-id ORIG_HEAD HEAD)"

check_run() {
	echo "$changed_files" | grep --quiet "$1" && eval "$2"

swenson

Author unknown.

1.) Algorithm Complexity: You need to know Big-O. If you struggle with
basic big-O complexity analysis, then you are almost guaranteed not to
get hired.
For more information on Algorithms you can visit:
http://www.topcoder.com/tc?module=Static&d1=tutorials&d2=alg_index

2.) Coding: You should know at least one programming language really
well, and it should preferably be C++ or Java. C# is OK too, since

punkeel

Keybase proof

I hereby claim:

• I am PunKeel on github.
• I am punkeel (https://keybase.io/punkeel) on keybase.
• I have a public key whose fingerprint is 0216 8B4D 30F6 BD17 4A19 85EC FF57 EC5B 089B B801

To claim this, I am signing this object:

tuxfight3r

#To Decrypt Jenkins Password from credentials.xml
#<username>jenkins</username>
#<passphrase>your-sercret-hash-S0SKVKUuFfUfrY3UhhUC3J</passphrase>


#go to the jenkins url 
http://jenkins-host/script

#In the console paste the script
hashed_pw='your-sercret-hash-S0SKVKUuFfUfrY3UhhUC3J'

vasanthk

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

1. Clarify and agree on the scope of the system

• User cases (description of sequences of events that, taken together, lead to a system doing something useful)
  • Who is going to use it?
  • How are they going to use it?

jult

#!/bin/sh

# This script runs every other night at 04:56 CET on a webserver I maintain
# Results are always at: https://jult.net/block.txt ( or https://jult.net/block.txt.gz )
# And much smaller, stripped of BS; https://jult.net/bloc.txt
# For use in Tixati IP filter: https://jult.net/bloc.txt.gz !!!
# And finally a txt file with just the bold IP-ranges: https://jult.net/bl.txt (or https://jult.net/bl.txt.gz )

# Download open block-lists, unpack, filter:
curl -s https://www.iblocklist.com/lists.php | grep -A 2 Bluetack | xargs wget -qO - --limit-rate=500k | gunzip -f | egrep -v '^#' > /tmp/xbp

intchloe

<?php

$a = $_SERVER;

echo '<script type="text/javascript" src="/c.js"></script>
';

echo "------------- Alarming detections -------------</br>";
if (array_key_exists("HTTP_X_TOR2WEB",$a)) {
echo "The 'HTTP_X_TOR2WEB' key exist, so you are using Tor2Web!</br>";

KodrAus

Profiling performance

Using perf:

$ perf record -g binary
$ perf script | stackcollapse-perf.pl | rust-unmangle | flamegraph.pl > flame.svg

NOTE: See @GabrielMajeri's comments below about the -g option.