Programming :: Shell Script - Which Should Diff Between PS Outputs

I would like to make a one-liner, which diff's "ps aux" output before and after killing a process. So basically it should be a combination of fallowing commands:
1) diff -u
2) ps aux | awk '{print $2}'
3) kill `ps aux | grep [c]ron | awk '{print $2}'`
4) ps aux | awk '{print $2}'

How to achieve this? Something like this:
Code:
diff $( kill `ps aux | grep [c]ron | awk '{print $2}'` && ps aux | awk '{print $2}' ) $( ps aux | awk '{print $2}' )
I don't have pgrep or pkill available.