-b

This is used to spawn a new branch from the checked out position mentioned with the commit ID.

git checkout –b <your_branch_name> is a short form of git checkout branch followed by git checkout <branch_name>.

This command creates a new reference inside .git/refs/heads/ with that particular commit ID.

--track

This parameter is used to set up the upstream configuration usually while creating a new branch with the –b parameter.

When executed, a separate section is added to the .config file inside the .git directory as follows:

[branch "master"]
        remote = origin
        merge = refs/heads/master

This happens when a command like git checkout --track -b master origin/master is executed.