cron jobs...

I need to start a job every friday night at 8:00 P.M , it runs all the day on Sat and Sun....can somebody tell me how to do this...I understand crontab...but haven't used it.........can u write some steps.....how to create a file and call.....I honestly dont know? Plz help.Thanks

tthis will do i guess

0 20 * * 5 script_name

I currently use vi, so I do this-

set editor=VI
crontab -e

Then once you're in there, add your line then save and exit out.

First column=minutes, 2nd=hour, 3rd=day, 4th=month, 5th=weekday, from 6th to end of line=command to execute. * in one of first 5 fields means any/every value, i.e., every minute, hour, day, etc.