How to get PID from ps command in linux?

Question

linux

Command `ps -e | grep ghc produces:

21965 ?        00:00:00 runghc
21966 ?        00:00:12 ghc

How to change the command to get not strings but only PID values?

Answer 1

ps -e | grep ghc | awk '{print $1}'

Answer 2

I upvoted the previous authors, of course, but awk is not needed here at all.
ps -A -o pid is sufficient.

Answer 3

ps -e | awk '/ghc/ {print $1}'

Answer 4

pgrep ghc