I wanted to edit the crontab on a Solaris 10 box, but when I tried to execute crontab -e, it didn't take me to the vi editor. This is what I got instead:
# crontab -e
No matter what I typed, I couldn't use this edit mode.
Turns out my terminal wasn't exported properly and vi started in 'one line' mode. Here's how to get the default vi back - you need to have the properly variables set in your shell:
# export EDITOR
# export TERMINAL
Now, try crontab -e again, and vi should be 'full screen'.