CRONTAB IN USE
The following is an example -
------------- minute (0 - 59)
| ----------- hour (0 - 23)
| | --------- day of month (1 - 31)
| | | ------- month (1 - 12)
| | | | ----- day of week (0 - 6) (Sunday=0)
| | | | |
* * * * * command executed
Key to abbreviations -
a) List of values – “,”
b) Range of values – “-“
c) Values of a field – “*”
d) To skip number of values – “/”
e) crontab -1 – Edit crontab
f) crontab –e – Root to run a command
g) sudo crontab –e – In case if any output is produced, cron daemon sends an email to the user.
h) /dev/null 2>&1 – To redirect the output to /dev/null.
