akalin

Direct links to Lecture Notes in Mathematics (Part 1)

*-Autonomous Categories - Michael Barr (1979) ([1], [2], [3], [4], [5], [6])

1-Dimensional Cohen-Macaulay Rings - Eben Matlis (1973) ([1], [2

bishboria

These links no longer work. Springer have pulled the free plug.

Graduate texts in mathematics

duplicates = multiple editions

A Classical Introduction to Modern Number Theory, Kenneth Ireland Michael Rosen

A Classical Introduction to Modern Number Theory, Kenneth Ireland Michael Rosen

aggrolite

Writing a reddit bot with Go and OAuth2

• Preface
• Quick Start
• Implicit Grant Authorization
• See Also

Preface

klzgrad

朴素VPN：一个纯内核级静态隧道

由于路由管控系统的建立，实时动态黑洞路由已成为最有效的封锁手段，TCP连接重置和DNS污染成为次要手段，利用漏洞的穿墙方法已不再具有普遍意义。对此应对方法是多样化协议的VPN来抵抗识别。这里介绍一种太简单、有时很朴素的“穷人VPN”。

朴素VPN只需要一次内核配置（Linux内核），即可永久稳定运行，不需要任何用户态守护进程。所有流量转换和加密全部由内核完成，原生性能，开销几乎没有。静态配置，避免动态握手和参数协商产生指纹特征导致被识别。并且支持NAT，移动的内网用户可以使用此方法。支持广泛，基于L2TPv3标准，Linux内核3.2+都有支持，其他操作系统原则上也能支持。但有两个局限：需要root权限；一个隧道只支持一个用户。

朴素VPN利用UDP封装的静态L2TP隧道实现VPN，内核XFRM实现静态IPsec。实际上IP-in-IP隧道即可实现VPN，但是这种协议无法穿越NAT，因此必须利用UDP封装。内核3.18将支持Foo-over-UDP，在UDP里面直接封装IP，与静态的L2TP-over-UDP很类似。

创建一个朴素VPN

justecorruptio

M[16],X=16,W,k;main(){T(system("stty cbreak")
);puts(W&1?"WIN":"LOSE");}K[]={2,3,1};s(f,d,i
,j,l,P){for(i=4;i--;)for(j=k=l=0;k<4;)j<4?P=M
[w(d,i,j++)],W|=P>>11,l*P&&(f?M[w(d,i,k)]=l<<
(l==P):0,k++),l=l?P?l-P?P:0:l:P:(f?M[w(d,i,k)
]=l:0,++k,W|=2*!l,l=0);}w(d,i,j){return d?w(d
-1,j,3-i):4*i+j;}T(i){for(i=X+rand()%X;M[i%X]
*i;i--);i?M[i%X]=2<<rand()%2:0;for(W=i=0;i<4;
)s(0,i++);for(i=X,puts("\e[2J\e[H");i--;i%4||
puts(""))printf(M[i]?"%4d|":"    |",M[i]);W-2

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

antirez

#!/usr/bin/tclsh8.5
#
# Usage: git-unmerged branch1 branch2
# 
# Shows all the non-common commits in the two branches, where non-common
# commits means simply commits with a unique commit *message*.

proc getlog branch {
    lrange [split [exec git log $branch --oneline] "\n"] 0 400
}

jjgod

Hardware

If you are interested, see also my previous setup.

I use a Mid 2013 11-inch MacBook Air at home.

I use Logitech Performance MX mice with all three of them, though for the last one is usually just the trackpad. I have recently started using a Logitech MX Master and decided to only buy that from now on.

adammw

Node.js for Raspberry Pi

Pre-built binaries

Recent releases have been pre-built using cross-compilers and this script and are downloadable below.

If you have found these packages useful, give me a shout out on twitter: @adammw

jbryer

require(ggplot2)
require(grid)

theme_update(panel.background=theme_blank(), 
			 panel.grid.major=theme_blank(), 
			 panel.border=theme_blank())

#Borrowed (i.e. stollen) from http://research.stowers-institute.org/efg/R/Color/Chart/ColorChart.R
getColorHexAndDecimal <- function(color) {
	if(is.na(color)) {