du command takes a little while to run, depending on what directory you pass it as a parameter, but then prints you a list of all the subdirectories along with their sizes.
Most common usage is shown below, -s parameter makes the command report a summary of disk usage stats for only the specified directories matching the /usr/* mask (and not their subdirectories), and -k specifies that we want to see the results in kilobytes:
du -sk /usr/*
