Link - using a chain of bash commands as a temporary file
Might come in handy one day.
For fun, you can see the temporary file created by the process: dir <( sort A | tr [:lower:] [:upper:] ) lr-x------ 1 crash daily 64 Mar 5 23:17 /dev/fd/63 -> pipe:[21483501]
Read more: Diff two stdout streams « crashingdaily