What are corn jobs and how can i use it . Moreover can i use it with webhosting account with linux server ? if yes how ?
First of all,it's not a "corn job" its a "cron job".
cron job can be used to schedule according to user specification.
All instruction or jobs to be schedule can be find in "crontab" file.
I won't give you full detail about it,instead check this link
http://www.adminschoice.com/docs/crontab.htm
Regarding web hosting account:
Of course you can use it with that account, as long as cron is installed on remote server