Linux scheduled task

Note: - The newly created cron job will not be executed immediately, at least 2 minutes to execute. If you restart cron, it will be executed immediately. - Pay attention to environment variables. Sometimes we create a crontab, but this task can't be executed automatically, but there is no problem in manually performing this task. This situation is generally caused by the absence of configuration environment variables in the crontab file. Don't assume that cron knows the special environment you need, it doesn't actually know. So you have to ensure that all necessary paths and environment variables are provided in the shelll script, except for some automatically set global variables.