Useful resources for pretty-printing and uglifying JSON at the command line can be found here.
A particularly useful method is to use Ruby's ppjson.
To use ppjson:
1. Install ppjson at the command line:
gem install ppjson
2. To pretty print the JSON and write the prettified version back to the file (as opposed to having it merely pour into the terminal console), run:
ppjson -fi abc123.json