VI commands for day to day working:
Note: **Press ESC key to come out of VI
:q -> to quit
:w -> to write
:qw -> to write and quite
:qw! -> to write and quite forcefully
h -> to move cursor left
j -> to move cursor down
k -> to move cursor up
L -> to move cursor down
x -> to delete a...
crontab syntax: minute hour day_of_month month weekday command
and you can use crontab -v : It'll display the last time you edited your crontab file. (**Note: This option is only available in few systems)