How to find out the version of installed cocoa pods?

EDIT

Based on your clarification you're looking for pod outdated. You can see more information about this with pod outdated --help

Original answer before question was edited

The command you want is pod --version

In the future you should use pod --help to find answers such as this. You can also use pod COMMAND --help to get help for specific commands.

You will find the version # in your Podfile.lock of all the pods you are currently using in your project. You will find this file at the same location as your Podfile.

This is how mine looks like:

PODS:
  - Alamofire (3.4.1)
  - EPSignature (1.0.2)
  - Kingfisher (2.4.2)
  - MBProgressHUD (0.9.2)
  - SwiftyJSON (2.3.2)

DEPENDENCIES:
  - Alamofire (~> 3.4)
  - EPSignature
  - Kingfisher
  - MBProgressHUD (~> 0.9.1)
  - SwiftyJSON

SPEC CHECKSUMS:
  Alamofire: 01a82e2f6c0f860ade35534c8dd88be61bdef40c
  EPSignature: 1f925f20b837046de46b4d396bc6e432ea383908
  Kingfisher: 05bf8d04408aaa70fcd2c8c81b9f1d0f1ad313dd
  MBProgressHUD: 1569cf7ace17a8bac47aabfbb8580a49690386d1
  SwiftyJSON: 04ccea08915aa0109039157c7974cf0298da292a

PODFILE CHECKSUM: 95eb36b090480f40d91543881d6ddb76bb1b8ca8

COCOAPODS: 1.0.1