shufengh

import sys

def cidr_to_subnet(ip_cidr):
    """Convert IP/CIDR format to IP Subnet Mask format."""
    ip, cidr = ip_cidr.split('/')
    cidr = int(cidr)
    mask = ((1 << cidr) - 1) << (32 - cidr)
    subnet_mask = ".".join(str((mask >> i) & 0xff) for i in [24, 16, 8, 0])
    return "{} {}".format(ip, subnet_mask)

shufengh

if your docker complains about permission denied to access a socket, try

sudo groupadd docker
sudo usermod -aG docker $USER
newgrp docker
# Fix existing permission issues
sudo chown "$USER" /home/"$USER"/.docker -R
sudo chmod g+rwx "$HOME/.docker" -R

shufengh

Original idea is from this post

1. Open a tab and navigate to the website where you have content to export.

2. Open devtools and switch to the console tab.

3. Copy and paste the following snippet in the console and Chrome should ask you to save the output file

var obj = JSON.stringify(localStorage, null, 4)

shufengh

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?

shufengh

I saw these questions in other places and think it may be worth a try. 
Question 1:

Given a finite set of unique numbers, find all the runs in the set. 
Runs are 1 or more consecutive numbers.
That is, given {1,59,12,43,4,58,5,13,46,3,6}, 
the output should be: {1}, {3,4,5,6}, {12,13}, {43}, {46},{58,59}.
Note that the size of the set may be very large.

If you think it's too easy, you can take a look at the discussion here: