ERROR: Error installing json: ERROR: Failed to build gem native extension

Its a late response, but may it helps someone else. to install json '1.8.3' it requires packages 'libgmp3-dev'.

Use following steps:

sudo apt-get install libgmp3-devgem install json -v '1.8.3'

For anyone who has this issue on Sierra, I solved the problem through this thread: https://teamtreehouse.com/community/installing-ruby-on-mac-got-error

Coles notes version is that after updating to most recent version of XCode, I had to accept the terms for the XCode command line tools. See them/agree to them by running:

gcc --version

After I did that, everything installed as expected.

To help you here are some steps to follow in order to install your gem locally:

1. Download json-1.8.3.
2. Place the downloaded gem into a folder called gems
3. Open the Ruby cmd console (click on start button, select Ruby then select "Start command prompt with Ruby")
4. cd to the gems folder. If the path to the folder is C:\Desktop\gems, write the command: cd C:\Desktop\gems then click "Enter".

5. To install the gem run the following command:

   gem install --local json-1.8.3.gem

I tried it and it worked for me, hopefully it will work for you.

Result:

Second way:

Include the whole path of the gem in the command:

gem install --local C:\Users\kedarl\Desktop\T\json-1.8.2.gem

For me here is the result. (This time with the json-1.8.2.gem):