# As others have pointed out, the first thing is to make sure you're
# using an editor you like.
# We're all admins here, so we all like vi (ducks, runs).
export VISUAL=vi
crontab -e
# (do some edits, finishing with ESCAPE)
:wq # ENTER
crontab -e # open user crontab in edit mode
i # for insert. Make your changes
:wq! # quit and save
crontab -l # open user crontab in read mode