脚本的最大优势，就是简化工作步骤提高工作效率，你看出来了吗？有没有看到这段代码的作用呢？

下面这段代码，是为了提高刷机的生产效率！掌握基本的shell编程，很多事情都会变得如此的简单。

update.sh

#! /bin/sh
set -x
echo "start update ..."

if [ -f /mnt/sd_card/aoni_update/app_5.1.6.jffs2 ] && [ -f /mnt/sd_card/aoni_update/close_watchdog ] && [ -f /mnt/sd_card/aoni_update/gm_led ];then
echo "file exist.continue!!"
else
echo "file not exist.exit!!!"
exit 0
fi

PROCESS_NUM_1=`ps | grep "main.V5.1.4.exe" | grep -v "grep" | wc -l`
PROCESS_NUM_2=`ps | grep "main.V5.1.5.exe" | grep -v "grep" | wc -l`
PROCESS_NUM_3=`ps | grep "main.V5.1.6.exe" | grep -v "grep" | wc -l`
PROCESS_watchdog=`ps | grep "close_watchdog" | grep -v "grep" | wc -l`

if [ $PROCESS_watchdog -eq 1 ];then
echo "Actually was runed upgrade.sh !!!!"
exit 0
fi

NAME=main.V5.1.4.exe

if [ $PROCESS_NUM_1 -eq 1 ]; then
NAME=main.V5.1.4.exe
fi
if [ $PROCESS_NUM_2 -eq 1 ]; then
NAME=main.V5.1.5.exe
fi
if [ $PROCESS_NUM_3 -eq 1 ]; then
NAME=main.V5.1.6.exe
fi

main_ID=`ps | grep "$NAME" | grep -v "grep" | awk '{print $1}'`
echo $main_ID
kill -9 $main_ID
echo "kill main_ID done!!!"
echo "---------------"

daemon_ID=`ps | grep "daemon.exe" | grep -v "grep" | awk '{print $1}'`
echo $daemon_ID
kill -9 $daemon_ID
echo "kill daemon_ID done!!!"
echo "---------------"

udhcpc_ID=`ps | grep "udhcpc" | grep -v "grep" | awk '{print $1}'`
echo $udhcpc_ID
kill -9 $udhcpc_ID
echo "kill udhcpc_ID done!!!"
echo "---------------"

echo close watchdog ...
cp /mnt/sd_card/aoni_update/close_watchdog /tmp
cp /mnt/sd_card/aoni_update/gm_led /tmp
cd /tmp
./close_watchdog &

if [ $? -eq 0 ];then

echo umount /mnt/mtd
umount /mnt/mtd
if [ $? -eq 0 ];then
echo "umount /mnt/mtd done!"

flash_eraseall /dev/mtd4

if [ $? -eq 0 ];then
echo "flash_eraseall done!"

flashcp /mnt/sd_card/aoni_update/app_5.1.6.jffs2 /dev/mtd4
if [ $? -eq 0 ];then
echo "flashcp done!"
echo "sync ..."
sync
echo "uptade success!!"
if [ $? -eq 0 ];then
./gm_led &
fi
fi
fi
fi

fi


另外补充一个问题就是关于看门狗的，umount分区之前，必须先kill掉存在该分区的进程，但是由于启用了看门狗，如果直接kill线程，看门狗就会一直重启系统而无法正常工作，首先第一想法是直接强制关闭，尝试了命令和程序貌似不太好使，干脆！直接不停的喂狗！代码如下：
close_watchdog.c 

#include <fcntl.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <linux/watchdog.h>
#define TIMEOUT 10
#define WDT_DEVICE_FILE "/dev/watchdog"
int main(void)
{
int g_watchdog_fd = -1;
int timeout = 0;
char arg = 1;

g_watchdog_fd = open(WDT_DEVICE_FILE, O_RDWR);
if (!g_watchdog_fd)
{
printf("Error in file open WDT device file(%s)...\n", WDT_DEVICE_FILE);

return 0;
}
ioctl(g_watchdog_fd, WDIOC_SETOPTIONS, WDIOS_ENABLECARD);
#if 1
ioctl(g_watchdog_fd, WDIOC_GETTIMEOUT, &timeout);
printf("default timeout %d sec.\n", timeout);

printf("We reset timeout as %d sec.\n", TIMEOUT);
timeout = TIMEOUT;
ioctl(g_watchdog_fd, WDIOC_SETTIMEOUT, &timeout);
ioctl(g_watchdog_fd, WDIOC_GETTIMEOUT, &timeout);
if (timeout != TIMEOUT)
{
printf("WDT timeout reset error.\n");
return 1;
}

while (1)
{
write(g_watchdog_fd, &arg, sizeof(arg));
ioctl(g_watchdog_fd, WDIOC_KEEPALIVE, 0);
sleep(2);
}
#endif
ioctl(g_watchdog_fd, WDIOC_SETOPTIONS, WDIOS_DISABLECARD);
close(g_watchdog_fd);
printf("watchdog_disable_dog!!!\n");
return 0;
}