Hi

1. crontab -e
This command is used ONLY for editing/adding the crontabs in vi editor.
2. crontab -l
This command just dispalys all crontabs at once, the file is not affected
3. crontab -l | more
This command display the crontabs, incase you file happen to be large,
hit the spacebar to view more.
The file again is not affected.

P.S: Make sure you have spare copy of your crontab file somewhere

Regards
Sumedha