Use df command to report file system disk space usage (parition wise):
Just use my tutorial to get information about TOTAL hard disk size, hard disk partition size in Mega bytes etc
http://www.cyberciti.biz/faqs/2006/0...ddisk-size.php
http://www.cyberciti.biz/tips/determ...isk-quota.html
Purchase a book called Linux in Nutshell but best way to learn linux is install on your Desktop and search using google for specific topics. Also consider using Linux documentation site
http://www.tldp.org