wget http://www.strazzere.com/android/tcpdump
adb push tcpdump /data/local/tmp/tcpdump
adb chmod 755 /data/local/tmp/tcpdump

adb shell
shell@android:/ $ su
root@android:/ # /data/local/tmp/tcpdump -h                                    
tcpdump version 3.9.8
libpcap version 0.9.8
Usage: tcpdump [-aAdDeflLnNOpqRStuUvxX] [-c count] [ -C file_size ]
		[ -E algo:secret ] [ -F file ] [ -i interface ] [ -M secret ]
		[ -r file ] [ -s snaplen ] [ -T type ] [ -w file ]
		[ -W filecount ] [ -y datalinktype ] [ -Z user ]
		[ expression ]
root@android:/ # /data/local/tmp/tcpdump -p -vv -s 0 w /sdcard/capture.pcap

#!/bin/bash

export PATH=/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin

ping_count() {
  count=0
  `timeout 5 ping 192.168.1.1 | while read LINE; do
  {
        if [[ "${LINE}" =~ "64 bytes from" ]]; then
                let "count = $count + 1"
                echo "export count=$count"
        fi
  }
  done`
  echo $count
}


if [[ $(ping_count) < 1 ]]; then
        ifconfig wlan0
        ifconfig wlan0 down
        sleep 1
        ifconfig wlan0 up
        sleep 1
        netcfg -r wlan0-Hugo-Nas
        sleep 5
        if [[ $(ping_count) < 1 ]]; then
                echo "Fatal error: wifi is down, rebooting now..."
                reboot
        fi
fi

curl -k https://dnsapi.cn/Domain.List -d "login_email=xxx&login_password=xxx" 

curl -k https://dnsapi.cn/Record.List -d "login_email=xxx&login_password=xxx&domain_id=xxx"

package dnspod

import (
	"io/ioutil"
	"net/http"
	"net/url"
	"strings"
)

const (
	login_email    = "<your_login_email>"
	login_password = "<your_login_password>"
	format         = "json"
	domain_id      = "<domain_id>"
	record_id      = "<record_id>"
	sub_domain     = "<your_subdomain>"
	record_type    = "CNAME"
	record_line    = "默认"
	ttl            = "600"
)

func Update(client *http.Client, cname string) string {
	body := url.Values{
		"login_email":    {login_email},
		"login_password": {login_password},
		"format":         {format},
		"domain_id":      {domain_id},
		"record_id":      {record_id},
		"sub_domain":     {sub_domain},
		"record_type":    {record_type},
		"record_line":    {record_line},
		"value":          {cname},
		"ttl":            {ttl},
	}
	req, err := http.NewRequest("POST", "https://dnsapi.cn/Record.Modify", strings.NewReader(body.Encode()))
	req.Header.Set("Accept", "text/json")
	req.Header.Set("Content-type", "application/x-www-form-urlencoded")
	resp, err := client.Do(req)
	if err != nil {
		return err.Error()
	}
	defer resp.Body.Close()
	bytes, _ := ioutil.ReadAll(resp.Body)
	return string(bytes)
}

var screen_chan chan int
var switch_chan = make(chan bool)

func main() {
	//a goroutine： 检查按键是否被按
	go func() {
		last_time := time.Now().UnixNano() / 1000000
		btn_pushed := 0
		total_mode := 3
		for msg := range WiringPiISR(PIN_GPIO_6, INT_EDGE_FALLING) {
			if msg > -1 {
				n := time.Now().UnixNano() / 1000000
				delta := n - last_time
				if delta > 300 { //如果两次按键变化的间隔时间<300ms，是因为接触信号不稳定可以忽略掉
					last_time = n
					btn_pushed++
					screen_chan <- btn_pushed % total_mode
				}
			}
		}
	}()

	//a goroutine： 根据管道消息刷新屏幕
	go loop_update_display()

	//选择确实的屏幕内容脚本编号
	screen_chan <- 0

	//a goroutine: 定时5s向管道发送更新屏幕内容的信号
	ticker := time.NewTicker(5 * time.Second)
	go func() {
		for {
			<-ticker.C
			screen_chan <- -1
		}
	}()
	
	...	
}

func loop_update_display() {
	current_screen := 0
	for msg := range screen_chan {
		switch_screen := false
		if msg >= 0 {
		   //说明是按钮触发的消息，而不是定时器触发的(-1)
			if msg != current_screen {
				//btn pushed
				current_screen = msg
				switch_screen = true
				go func() {
					select {
					case <-time.After(500 * time.Millisecond):
						display_loading()
						<-switch_chan
					case <-switch_chan:
					}
				}()
			}
		}
		switch current_screen {
		case 0:
			display_screen0()
		case 1:
			display_screen1()
		case 2:
			display_screen2()
		}
		if switch_screen {
			switch_chan <- true
		}
	}
}

go func() {
	select {
	case <-time.After(500 * time.Millisecond):
		display_loading(current_screen)
		<-switch_chan
	case <-switch_chan:
	}
}()

package main

import (
	"log"
)

var a, b, c int

func main() {
	a = 1
	b = 2
	c = a + 2
	log.Println(a, b, c)
}

package main

import (
	"log"
)

var a, b, c int

func main() {
	go func() {
		a = 1
		b = 2
	}()
	go func() {
		c = a + 2
	}()
	log.Println(a, b, c)
}

package main

import (
	. "github.com/hugozhu/rpi"
	"github.com/hugozhu/rpi/pcd8544"
	"log"
	"os/exec"
	"time"
)

const (
	DIN        = PIN_MOSI
	SCLK       = PIN_SCLK
	DC         = PIN_GPIO_2
	RST        = PIN_GPIO_0
	CS         = PIN_CE0
	PUSHBUTTON = PIN_GPIO_6
	CONTRAST   = 40 //may need tweak for each Nokia 5110 screen
)

var screen_chan chan int
var TOTAL_MODES = 3

func init() {
	WiringPiSetup()
	pcd8544.LCDInit(SCLK, DIN, DC, CS, RST, CONTRAST)
	screen_chan = make(chan int, 1)
}

func main() {
	//a goroutine to check button push event
	go func() {
		last_time := time.Now().UnixNano() / 1000000
		btn_pushed := 0
		for pin := range WiringPiISR(PUSHBUTTON, INT_EDGE_FALLING) {
			if pin > -1 {
				n := time.Now().UnixNano() / 1000000
				delta := n - last_time
				if delta > 300 { //software debouncing
					log.Println("btn pushed")
					last_time = n
					btn_pushed++
					screen_chan <- btn_pushed % TOTAL_MODES //switch the screen display
				}
			}
		}
	}()

	//a groutine to update display every 5 seconds
	go loop_update_display()

	//set screen 0 to be default display
	screen_chan <- 0

	ticker := time.NewTicker(5 * time.Second)

	for {
		<-ticker.C
		screen_chan <- -1 //refresh current screen every 5 seconds
	}
}

func loop_update_display() {
	current_screen := 0
	for screen := range screen_chan {
		if screen >= 0 {
			if screen != current_screen {
				//btn pushed
				current_screen = screen
				display_loading()
			}
		}
		switch current_screen {
		case 0:
			display_screen0()
		case 1:
			display_screen1()
		case 2:
			display_screen2()
		}
	}
}

func display_loading() {
	pcd8544.LCDclear()
	pcd8544.LCDdrawstring(0, 20, "Loading ...")
	pcd8544.LCDdisplay()
}

func display_screen0() {
	out, err := exec.Command("/bin/screen_0.sh").CombinedOutput()
	if err != nil {
		out = []byte(err.Error())
	}

	pcd8544.LCDclear()
	pcd8544.LCDdrawstring(0, 0, string(out))
	pcd8544.LCDdisplay()
}

func display_screen1() {
	out, err := exec.Command("/bin/screen_1.sh").CombinedOutput()
	if err != nil {
		out = []byte(err.Error())
	}

	pcd8544.LCDclear()
	pcd8544.LCDdrawstring(0, 0, string(out))
	pcd8544.LCDdisplay()
}

func display_screen2() {
	out, err := exec.Command("/bin/screen_2.sh").CombinedOutput()
	if err != nil {
		out = []byte(err.Error())
	}

	pcd8544.LCDclear()
	pcd8544.LCDdrawstring(0, 0, string(out))
	pcd8544.LCDdisplay()
}

mod_rpi on

####add it to tsar default output
output_stdio_mod mod_rpi

hugo@raspberrypi2 ~/projects/tsardevel $ tsardevel rpi 
build:make
install:make install
uninstall:make uninstall
hugo@raspberrypi2 ~/projects/tsardevel $ ls rpi
Makefile  mod_rpi.c  mod_rpi.conf

/*
 * (C) 2010-2011 Alibaba Group Holding Limited
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#include "tsar.h"

/*
 * Structure for rpi infomation.
 */
struct stats_rpi {
	unsigned int cpu_temp;
};

#define STATS_TEST_SIZE (sizeof(struct stats_rpi))

static char *rpi_usage = "    --rpi               Rapsberry Pi information (CPU temprature ...)";


static void read_rpi_stats(struct module *mod, char *parameter)
{
	FILE *fp;
	char buf[64];
	memset(buf, 0, sizeof(buf));
	struct stats_rpi st_rpi;
	memset(&st_rpi, 0, sizeof(struct stats_rpi));

	if ((fp = fopen("/sys/class/thermal/thermal_zone0/temp", "r")) == NULL) {
		return;
	}

	int cpu_temp;

	fscanf(fp, "%d", &cpu_temp);

	st_rpi.cpu_temp = cpu_temp;

	int pos = sprintf(buf, "%u",
			/* the store order is not same as read procedure */
			st_rpi.cpu_temp);
	buf[pos] = '\0';
	set_mod_record(mod, buf);
	fclose(fp);
	return;
}

static struct mod_info rpi_info[] = {
	{"  temp", SUMMARY_BIT,  0,  STATS_NULL}
};

static void set_rpi_record(struct module *mod, double st_array[],
		U_64 pre_array[], U_64 cur_array[], int inter)
{
	st_array[0] = cur_array[0]/1000.0;
}

void mod_register(struct module *mod)
{	
	register_mod_fileds(mod, "--rpi", rpi_usage, rpi_info, 1, read_rpi_stats, set_rpi_record);
}