Cron syntax is used to schedule tasks to run at specific times or intervals. A cron expression consists of five fields, representing different time units, plus an optional sixth field for the year:
  1. Minute (0-59)
  2. Hour (0-23)
  3. Day of Month (1-31)
  4. Month (1-12 or Jan-Dec)
  5. Day of Week (0-6 or Sun-Sat)
  6. Year (optional, e.g., 2023)
Each field can contain:
  • A specific value (e.g., 5 for the 5th minute)
  • A range (e.g., 1-5 for minutes 1 through 5)
  • A list (e.g., 1,15,30 for minutes 1, 15, and 30)
  • A step value (e.g., /15 for every 15 minutes)
  • Wildcard “ to represent all possible values in that field.
Creating Custom Cron Expressions: To create a custom cron expression, you need to define the schedule by specifying the desired values in each field. For example:
  • Every day at midnight: 0 0 * * *
  • Every Monday at 8 AM: 0 8 * * 1
  • Every 15 minutes: /15 * * * *
This flexibility allows you to schedule tasks with precision according to your needs.