cron in ubuntu

How to write cron in ubuntu

cron is use to perform we repetable jobs which is done in system each and every second or minute

when we install ubuntu it will come defaultly

sudo yum install vixie-cron crontabs
#chkconfig crond on

#/service crond start

for suppose you would like to perform a command like example each every minute then you can do like this

it is in the below format

minutes hours (date of month) (month) (day of the weak) command

16 9 * * * chmod -R 777 /var/managment/*

here in the above we had given as every morning at 9hours 16minutes on every day every month this command will be executed

for suppose you would like to perform it for every 10 minutes means here it will be like this

*/10 * * * * chmod -R 777 /var/managment/*

so here the will will be runned for every 10 minutes,

if would like to run for every minute means then do like this

* * * * * chmod -R 777 /var/managment/*

so here the command will be runned for every minute

To check the cron running in your system then type like this

#crontab -l

to restart the cron then

#service crontab restart