instead of "ls -1" you could use any other command that returns a list
The "du -hs ." will only return the size of the current directory, but that was also an example. You could use any other command that you wanted to perform over each item in the list returned by the first command.
Not sure if this is clear enough, please let me know.
ctrl + z
then, to send it to the background:
bg
and, to get it back from the background:
fg
Also, I really like to use "for", like:
// get the size of each file or directory in the current directory
for i in `ls -1`; do du -hs $i; done;