liaoyw

Bash Shortcuts

Moving

command	description
ctrl + a	Goto BEGINNING of command line

liaoyw

package main

import (
	"bytes"
	"crypto/aes"
	"crypto/cipher"
	"encoding/base64"
	"fmt"
)

liaoyw

enum { BMAX = 32, BMIN = BMAX / 2, BHEIGHT = 6 };

struct BNode {
    uint32_t length;
    Key keys[BMAX];
    union {
        BNode *children[BMAX];
        Value values[BMAX];
    };
};

liaoyw

##TCP FLAGS##

Unskilled Attackers Pester Real Security Folks
==============================================
                     TCPDUMP FLAGS
Unskilled =  URG  =  (Not Displayed in Flag Field, Displayed elsewhere) 
Attackers =  ACK  =  (Not Displayed in Flag Field, Displayed elsewhere)
Pester    =  PSH  =  [P] (Push Data)
Real      =  RST  =  [R] (Reset Connection)
Security  =  SYN  =  [S] (Start Connection)

liaoyw

import java.io.File;
import java.util.*;
import java.lang.management.BufferPoolMXBean;
import java.lang.management.ManagementFactory;
import javax.management.MBeanServerConnection;
import javax.management.ObjectName;
import javax.management.remote.*;

import com.sun.tools.attach.VirtualMachine; // Attach API

liaoyw

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

liaoyw

• http://the-paper-trail.org/blog/distributed-systems-theory-for-the-distributed-systems-engineer/
• https://github.com/palvaro/CMPS290S-Winter16/blob/master/readings.md
• http://muratbuffalo.blogspot.com/2015/12/my-distributed-systems-seminars-reading.html
• http://christophermeiklejohn.com/distributed/systems/2013/07/12/readings-in-distributed-systems.html
• http://michaelrbernste.in/2013/11/06/distributed-systems-archaeology-works-cited.html
• http://dancres.org/reading_list.html
• http://rxin.github.io/db-readings/
• http://research.microsoft.com/en-us/um/people/lamport/pubs/pubs.html
• http://www.eecs.berkeley.edu/GradAffairs/CS/Prelims/db.html
• http://pdos.csail.mit.edu/dsrg/papers/

liaoyw

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

liaoyw

import os
"""
as bash command: du -sb dir
+4906: add 4096bytes for the top dir
"""
def du_sb(dir):
 return sum(os.path.getsize(f) for f in reduce(lambda x,y:x+y, [[os.path.join(w[0], fe) for fe in w[1] + w[2]]  for w in os.walk(dir)])) + 4096;

def get_total_file_size(dir):
    return sum(os.path.getsize(f) for f in reduce(lambda x,y:x+y, [[os.path.join(w[0], fe) for fe in w[1] + w[2]]  for w in os.walk(dir)]) if os.path.isfile(f))