How can I see the colored log using tail or less?
pass -R to less for it to let colour escape sequences pass through, i.e.
less -R log/development.logThis should result in them being displayed in colour, assuming you are using the proper terminal type
tail -f log/development.log | ccze -AYou may need to install ccze
sudo apt-get install cczeit works better, not ideal but works
You can't do that out of the box, since tail and less know nothing about Rails, and logs are saved a simple text files. You could use regular expressions to colorize output but I doubt it's worth the trouble.
EDIT: see alfonso's comment for some alternatives.