SHELL

how to sign into github from terminal

$ git config --global user.name "John Doe"
$ git config --global user.email johndoe@example.com

or to see the signed in user

git config --list

how to login github in terminal

All these methods are outdated:

You need to use a personal Token to log in. Below are the steps

1)Log in to GitHub and navigate to the Settings
2)Click on Developer Settings
3) Click on Personal Access Tokens
4)Click on Generate new token
5) Now type in the name of the token and select the scopes, 
or permissions, you’d like to grant this token. 
Make sure you select repo to use your token to access 
repositories from the command line. Click Generate token.

NOW COPY THE TOKEN AND PASTE IT WHEN GITHUB ASKS FOR PASSWORD FROM THE TERMINAL
 it your new password
OR FILL  JUST THIS WITH THE NECCESARY DETAILS
git push https://<GITHUB_ACCESS_TOKEN>@github.com/<GITHUB_USERNAME>/<REPOSITORY_NAME>.git