= WC - Word Count =

Count lines or words. ls | wc -l //Count the number of files in a directory

List, Print 1st or n'th column, sort, unique, count entries: last | awk '{ print $1}' | sort | uniq | wc -l

Sort by Memory Usage: ps aux | sort -n -k4 //think of k meaning sort by column number. //another method just for ps: ps aux –sort:rss //explaination for memory usage: http://unix.derkeiler.com/Newsgroups/comp.unix.aix/2007-07/msg00026.html

man wc for other usage.