I am writing this blog after my struggle to install google cloud SDK in macOS (Sierra).
1. First download the official Google Cloud SDK archive file from here.
2. Unzip the archive and save it at your desired folder.
3. Now open the folder which contains your unzipped
google-cloud-sdk folder in terminal.
4. Run the command
sh ./google-cloud-sdk/install.sh and give yes to all further prompts and you are done.
Now, just type
gcloud -v to verify your installation. If you find your gcloud version in your terminal, then you have successfully installed google cloud sdk.
Now the command
gcloud will be available globally anywhere in your terminal!