SOURCE: http://www.khmer365.com/index.php?topic=3791.0

To  change default VI Editor to Nano (Temporary)> Type the command as follows:

1. which nano

2. export EDITOR=/usr/bin/nano

3. crontab -e

To  change default VI Editor to Nano (Permanent) > Type the command as follows:

nano /etc/profile

To  change default VI Editor to Nano (Permanent) > ADD This Code to Profile:

export EDITOR=/usr/bin/nano