Crontab Example

Crontab file
___________
Crontab syntax :-
A crontab file has five fields for specifying day , date and time followed by the command to be run at that interval.

* * * * * command to be executed
- - - - -
| | | | |
| | | | +----- day of week (0 - 6) (Sunday=0)
| | | +------- month (1 - 12)
| | +--------- day of month (1 - 31)
| +----------- hour (0 - 23)
+------------- min (0 - 59)

Run-levels in AIX

Run-level Description

0-1 Reserved for the future use of operating system.

2 Contains all of the terminal process and daemons that are run in the multiuser environment. This is the default run-level.

3-9 Can be defined according to the user-preferences.

a,b,c,h These are not true run levels; they differ from run levels in that the init command cannot request the entire system to enter these run-levels.

S,s,M,m Maintainance mode. When the system enters maintainance made from another run-level, only the system console is used as the terminal.