Available hard drive space
 

How would I find out how much space a folder takes up on the hard drive using the command line?

Try du -h FILENAME. du is the disk usage command - the -h option displays the result in human-readable format, if memory serves.

If that doesn't work, consult the man page for du and check out the available options. I'm not at a Linux box now, otherwise I'd check for you...

...or you might try command 'df'

For folders and such a du -sh /folder/path would do it. To see the sizes and usage of mounted filesystems a df-h will do.