chow1937

Open Files Limit

Changing Limit For Current Session

Most operating systems can change the open-files limit for the current shell session using the ulimit -n command:

ulimit -n 200000

Mac OS X El Capitan

ubershmekel

#!/usr/bin/python
"""
court.gov.il for some reason send out these signed files with the "sgn" file extension.

They're xml files with base64 encoded contents, this is how you can get them out.

    open_sgn.py myfile.sgn
"""

import base64

Firefishy

#!/bin/bash
set -e

JAVA_HOME=${1-text}
[ $# -eq 0 ] && { echo "Usage: sudo $0 \$(/usr/libexec/java_home -v '1.8*')" ; exit 1; }

KEYSTORE=$JAVA_HOME/jre/lib/security/cacerts

wget https://letsencrypt.org/certs/letsencryptauthorityx1.der
wget https://letsencrypt.org/certs/letsencryptauthorityx2.der

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?

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

mbbx6spp

Best UNIX Shell tools

These are a list of usages of shell commands I can't live without on UNIX-based systems.

Install

Mac OS X

Using Homebrew (yes, I am opinionated) you can install the following tools with the following packages: