If you are using Mac OS and If you are a developer, chances are that you will be often using QuickLook in the finder to preview file contents.
However you should have noticed that QuickLook will not let you preview plain text files without a file extension like
README INSTALL Capfile CHANGELOG etc...
If you need to preview such files, you can install a QuickLook plugin called QLStephen.
Install QLStephen using Homebrew:
Open your Terminal and run
brew cask install qlstephen
Install QLStepen using MacPorts:
port install qlstephen