Here we’ll see 3 basic rails commands to Identify which version of gems we are using.
In many instances our application does not support couple of gem version. in that case we need to detect what’s the exact version, then need to remove the unsupported version to make our app run cleanly.
Run below commands from your CMD / Terminal
Command 1 :
$ gem list
It will list all gem file names along with their complete version details.
Command 2 :
$ gem list will_paginate
This will list all version of will_paginate that our application is using.
Command 3 :
$ gem uninstall will_paginate
It will prompt list of gem versions and as per your need you can remove which ever you want.
In my case, rails 4.0.0 update got installed. but I could not manage that. I wanted rails 3.2 back for my application. I used above basic commands and fixed my issue. Hope that will help.