Display help information about git.
# To display help about a specific git subcommand:
git help <subcommand>
# To display help about a specific git subcommand in a web browser:
git help --web <subcommand>
# To display a list of all available git subcommands:
git help --all
# To list the available guides:
git help --guide
# To list all possible configuration variables:
git help --config