How to configure git to pull from one repository and push to another

Question

I have two remote repositories: a main repository and a fork, and want to pull new changes from the main repo and push to my fork so I can create pull-requests to the main repo.

I know it is posible to add both remotes using git remote add <name> <url> but I don't want to explicitly do git pull <main_repo> and git push <fork_repo>

Answer 1

git remote set-url --push origin <fork_repo>

After doing that you can check urls with this command

git remote -v

and you'll see something like

origin <main_repo> (fetch)
origin <fork_repo> (push) 

Answer 2

The solution for this is to add the main repository as the "origin" remote:

git remote add origin <main_repository_url>

Or if already exists:

git remote set-url origin <main_repository_url>

Then set the fork as the push url of the remote:

git remote set-url --push origin <fork_repository_url>

Just to check the results:

$ git remote -v
origin  <main_repository_url> (fetch)
origin  <fork_repository_url> (push)

And now it is possible to pull/checkout branches from the main repository and push changes to the fork.