Oracle Database Discussions

Hi, i'm an Oracle newbie. I heard it's possible to startup and shutdown an oracle (instance? or database? which one is it) from the command line.

A little background on what it is that I want to do:

I'm looking to backup a database by copying the files that make up the database to a location from where they will be commited to tape media. To do this I must shutdown the database, copy the files, and startup the database again.

At the moment the backups are full exports which I find unnecessary since it is a development database which is never used at night. It is therefore not an issue if we want to shut it down and re-start it after a few minutes. (I think it would take longer to export as opposed to copy the files right?)

I need help and advice :

1. Is my way of going about this correct ?
2. How do I startup/shutdown from the command line (sqlplus user/password command) or should I use another utility ?

Thanks,
Gabriel