What are some names of tools for checking disk space
 

What are some names of command line tools for checking disk space, memory, bandwidth.

Also with windows we had to defrag the hard drive can that be done in linux?

Just a big list of tools and what they do would be a nice.

Thanks

Use df to check disk space usage on all your filesystems. You can also use du to see how much space a particular directory is taking up. See the man pages for these commands for more informartion,

Linux systems don't become fragmented in the same way Windows ones do. Therefore, there's no need for you to have to run manual defrags (any fragmentation is corrected by the filesystem code itself).

Thanks for all your help!