# User Management
 
|   |   |
|---|---|
|Command|Description|
|sudo adduser \<user\>|Create a new user|
|sudo userdel \<user\>|Delete a user|
|sudo usermod -aG \<group\> \<user\>|Add a user to group|
|sudo deluser \<user\> \<group\>|Remove a user from a group|
 
# CRON
 
|   |   |   |
|---|---|---|
|Field|Allowed Values|Description|
|Second|0 - 59|Trigger every SECOND second(s)|
|Minute|0 - 59|Trigger every MINUTE minute(s)|
|Hour|0 -23|Trigger every HOUR hour(s)|
|Day|1 - 31|Trigger every DAY day(s) of month|
|Month|1 - 12|Trigger every MONTH month(s)|
|Doay of Week|0 - 6|MON-SUN Trigger on specific DAY OF WEEK|
 
# Special Characters
 
|   |   |
|---|---|
|Special Character|Description|
|*|Trigger on tick of every time unit|
|,|List separator|
|-|Specifies a range|
|/|Defines an increment|
 
# Examples
 
|   |   |
|---|---|
|Cron Expression|Description|
|0 * * * *|Executes every minute|
|0 0 * * * *|Executes every hour|
|0 0 0 * * *|Executes every day|
|0 0 0 0 * *|Executes every month|
|0 0 0 1 1 *|Executes on first day of Jan each year|
|30 20 * * SAT|Executes at 08:30pm every Saturday|
|30 20 * * 6|Executes at 08:30pm every Saturday|
|0 */5 * * * *|Executes every five minutes|
|0 0 8-10/1 * * *|Executes every hour between 8am and 10am|