crontab定時(shí)任務(wù)解釋

# Example of job definition:

# .---------------- minute (0 - 59)

# |? .------------- hour (0 - 23)

# |? |? .---------- day of month (1 - 31)

# |? |? |? .------- month (1 - 12) OR jan,feb,mar,apr ...

# |? |? |? |? .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat

# |? |? |? |? |

# *? *? *? *? * user-name? command to be executed