How much disk space do I have left (disk usage du and disk free df)

To see how much disk space you have left use df -h The h flag is for "human readable". Otherwise you get the size in 1k blocks. To see how much space a directory is using type du -hs h is again for human readable and s means summary - meaning only the total size is given. Without s you get recursively the size of every file below the directory.