linux定时任务如何每隔0.5秒执行一次呢？

Question

求一个例子！！！linux定时任务如何每隔0.5秒执行一次呢？

Answer 1

* * * * * for i in `seq 120`; do awesome_scripts& sleep 0.5; done

Scheduled by crontab every minute, each time it is invoked, the loop is executed 120 times with an interval of 0.5 seconds

Answer 2

Since crontab the minimum unit is minutes, you can only write your own program to execute it. Give an example of shell + python:

while true ; do ./your-script & ; python -c "import time;time.sleep(0.5)"; done

or python + shell:

import time
from subprocess import call
while(True):
    call(["./your-script"])
    time.sleep(0.5)

I don’t have linux, so I haven’t tested it myself. That’s probably the idea

Answer 3

Try it with watch
watch -n 0.5 date

Answer 4

It’s not convenient to test on a Windows machine, maybe something like this

#!/bin/bash
for i in {1..120}
do
  usleep 500
  RUN_YOUR_TASK&
done

Use usleep to sleep for half a second for one minute, just combine it with cron

Answer 5

Not found. It can only reach the level of minutes, not even seconds.

Answer 6

Let’s talk about your usage scenarios

Answer 7

The shortest definition of crontab can only be up to minutes, which can only be completed with the script sleep

Answer 8

When all the above methods are executed on Linux, a pit will appear and multiple processes will appear.
Because if there is a delay, after more than 60 seconds, the second scheduled task will start. Multiple processes will appear. process.
The solution is to add file lock /usr/bin/flock