ls

I know it sounds silly, but do you always remember all thouse switches

To list directory and sort by file size

ls -lahS

-rw-rw-rw-  1 xxx xxx 464M Sep 23 19:29 value_update_sum.rb.output
-rw-rw-rw-  1 xxx xxx 250M Sep 23 19:29 value_update_start.rb.output

du

To get to total size of particular folder in linux

du -hs /home