nutch1.4定时爬取数据配合linux定时任务可以实现nutch的自动定时爬取，linux定时任务请参考

 linux crontab 配置定时mapreduce job

http://www.aboutyun.com/thread-6289-1-1.html

(出处: about云开发)

步骤如下：

1、首先查看当前用户的 crontab服务执行命令：

crontab -l

执行结果：

no crontab for ***

表示没有定义 crontab 服务

观察运行结果。重启可能不成功，使用如下步骤重新启动：

15:40:34^O^bin$ sudo /etc/init.d/cron stop

 [sudo] password for sniffer: 

 Rather than invoking init scripts through /etc/init.d, use the service(8)

 utility, e.g. service cron stop

 Since the script you are attempting to invoke has been converted to an

 Upstart job, you may also use the stop(8) utility, e.g. stop cron

 cron stop/waiting

 15:40:49^O^bin$ ps -A | grep cron

 15:40:54^O^bin$ sudo /etc/int.d/cron start

 sudo: /etc/int.d/cron: command not found

 15:41:11^O^bin$ sudo /etc/init.d/cron start

 Rather than invoking init scripts through /etc/init.d, use the service(8)

 utility, e.g. service cron start

 Since the script you are attempting to invoke has been converted to an

 Upstart job, you may also use the start(8) utility, e.g. start cron

 cron start/running, process 14362

 15:41:19^O^bin$ ps -A | grep cron

 14362 ?        00:00:00 cron

注：nutch脚本存在无法找到JAVA_HOME的问题可以修改如下部分解决：

if [ "$JAVA_HOME" = "" ]; then

  #echo "Error: JAVA_HOME is not set."

  #exit 1

  JAVA_HOME="***"

fi