cron.md

   1 ---
   2 title: Cron
   3 category: CLI
   4 layout: 2017/sheet
   5 updated: 2018-05-03
   6 weight: -3
   7 ---
   8
   9 ## Format
  10 {: .-two-column}
  11
  12 ### Format
  13
  14 ```
  15 Min  Hour Day  Mon  Weekday
  16 ```
  17 {: .-setup}
  18
  19 ```
  20 *    *    *    *    *  command to be executed
  21 ```
  22
  23 ```
  24 ┬    ┬    ┬    ┬    ┬
  25 │    │    │    │    └─  Weekday  (0=Sun .. 6=Sat)
  26 │    │    │    └──────  Month    (1..12)
  27 │    │    └───────────  Day      (1..31)
  28 │    └────────────────  Hour     (0..23)
  29 └─────────────────────  Minute   (0..59)
  30 ```
  31 {: .-setup.-box-chars}
  32
  33 ### Operators
  34
  35 | Operator | Description                |
  36 | ---      | ---                        |
  37 | `*`      | all values                 |
  38 | `,`      | separate individual values |
  39 | `-`      | a range of values          |
  40 | `/`      | divide a value into steps  |
  41
  42 ### Examples
  43
  44 | Example        | Description                 |
  45 | ---            | ---                         |
  46 | `0 * * * *`    | every hour                  |
  47 | `*/15 * * * *` | every 15 mins               |
  48 | `0 */2 * * *`  | every 2 hours               |
  49 | `0 18 * * 0-6` | every week Mon-Sat at 6pm   |
  50 | `10 2 * * 6,7` | every Sat and Sun on 2:10am |
  51 | `0 0 * * 0`    | every Sunday midnight       |
  52 | ---            | ---                         |
  53 | `@reboot`      | every reboot                |
  54
  55 ### Crontab
  56
  57 ```bash
  58 # Adding tasks easily
  59 echo "@reboot echo hi" | crontab
  60 ```
  61
  62 ```bash
  63 # Open in editor
  64 crontab -e
  65 ```
  66
  67 ```bash
  68 # List tasks
  69 crontab -l [-u user]
  70 ```