我需要在cron中设置一个程序，该程序设置为每次程序终止时重新启动
为什么我想做这份工作？
该程序实际上是使用网络报废从网站中提取信息，当它到达信息是最新的点时终止 这是python代码的一部分
sql = """SELECT Short_link FROM Properties WHERE Short_link=%s"""
rows = cursor.execute(sql,(link_result))
print rows
if rows>=1:
print "Already present"
sys.exit()
else:
query="""INSERT INTO Properties (Published_Date, Title,Price,Bedroom,Agency_Fee, Bathroom, Size,Prop_ref,Furnished_status,Rent_payment,Building_info,Amenities,Trade_name,Licence, RERA_ID,Phone_info,Short_link) values (%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s)"""
cursor.execute(query,(date_result, title_result, price_result, bedroom_result, agencyfee_result, bathroom_result, size_result, propertyref_result, furnished_result, rent_is_paid_result, building_result, Amenities_result, tradename_result, licencenum_result, reraid_result, phone_result, link_result))
脚本如下： run.sh
#!/bin/bash
PATH=$PATH:/bin:/usr/bin
date +'%H:%M:%S Started' >> /home/ahmed/Desktop/log.txt
TMP_FILE=/tmp/i_am_running
[ -f $TMP_FILE ] && exit
touch $TMP_FILE
date +'%H:%M:%S Starting Python' >> /home/ahmed/Desktop/log.txt
/usr/bin/python /home/ahmed/Desktop/python.py
rm $TMP_FILE
date +'%H:%M:%S Ended' >> /home/ahmed/Desktop/log.txt
我使用的cron命令是* * * * * /home/ahmed/Desktop/run.sh
日志文件如下：
15:21:01 Started
15:21:02 Starting Python
15:22:02 Started
15:23:01 Started
15:24:01 Started
15:24:30 Ended
15:25:01 Started
15:25:01 Starting Python
15:26:01 Started
15:27:18 Started
15:28:01 Started
15:29:01 Started
15:30:01 Started
15:31:01 Started
15:31:16 Ended
15:32:01 Started
15:32:01 Starting Python
15:33:01 Started
15:34:01 Started
似乎程序在结束之前重新启动。日志文件应该有启动程序，启动，结束，启动程序，启动，结束等等。
有人可以指导我吗？也许在bash脚本中需要进行一些更改？如何将程序设置为启动，启动，结束等
答案 0 :(得分：0)
您可以使用另一个shell脚本来运行您自己的run.sh.例如
$ cat runner.sh
while [ 1 ]; do
./run.sh
if [ -e /tmp/stop_run ]; then
exit
fi
sleep 1
done
如果你需要停止这个脚本，只需触摸/ tmp / stop_run而不是杀死run.sh。
此解决方案您不需要cron。只需将runner.sh添加到/etc/rc.local
即可答案 1 :(得分：0)
程序在结束之前重新启动，因为你每天每小时都在运行cron作业......
* * * * * /home/ahmed/Desktop/run.sh
你需要做的是运行程序的无限循环，直到它完成并在循环结束时再次开始运行。只要你知道任务不会花费超过一分钟，每分钟运行一次程序就可以了。
所以我会这样做：
while(true){
PATH=$PATH:/bin:/usr/bin
date +'%H:%M:%S Started' >> /home/ahmed/Desktop/log.txt
# TMP_FILE=/tmp/i_am_running # Don't need this
# [ -f $TMP_FILE ] && exit # (Don't need to check if a the script is running)
# touch $TMP_FILE # (You don't need to create the file)
date +'%H:%M:%S Starting Python' >> /home/ahmed/Desktop/log.txt
/usr/bin/python /home/ahmed/Desktop/python.py
# rm $TMP_FILE # (I commented this as you don't need it)
date +'%H:%M:%S Ended' >> /home/ahmed/Desktop/log.txt
# You can add a 'sleep XX' to delay the script between executions in case you don't
# want it to be executed one time and another as soon as an execeution finishes.
# Remember to comment (add '#') or remove the line of cron (crontab -e)
}
你正在做的是每分钟运行一个程序实例，但它们只会在运行所花费的时间后完成：
15:21:01 Started (Start 1st program)
15:21:02 Starting Python (python script is executed, called from bash script)
15:22:02 Started (cron runs 2nd program, not execute python, exit)
15:23:01 Started (cron runs 3rd program, not execute python, exit)
15:24:01 Started (cron runs program, not execute python, exit)
15:24:30 Ended (End 1st program)
15:25:01 Started (cron runs 5th program)
15:25:01 Starting Python (execute 5th program's python script, called from bash script)
15:26:01 Started (etc..)
15:27:18 Started
15:28:01 Started
15:29:01 Started
15:30:01 Started
15:31:01 Started
15:31:16 Ended
15:32:01 Started
15:32:01 Starting Python
15:33:01 Started
15:34:01 Started
正如我告诉你的那样，在你的情况下，最好的方法是无限循环。但是如果你还是喜欢cron（我个人喜欢，因为无限循环并不总是最好的选择，你总是可以设置cron来每10,15或20分钟执行一次脚本，这是一个更好的选择。
*/10 * * * * /home/ahmed/Desktop/run.sh # This will exceute every 10 minutes
*/15 * * * * /home/ahmed/Desktop/run.sh # This will exceute every 15 minutes