What is a "switch" in a Git command?

Question

I was reading a book which shows the syntax of git commands as:

so my question is, is --global also a switch? Can a switch also a argument?

Updated:

the book said --global is a switch, so I assume -a is also a switch and we can use it as git help -a, but we can't use it as git -a help, which is supposed to be valid according to the syntax?

Answer 1

The switches are all the parameters passed before any Git actual command: see docs/git

git [--version] [--help] [-C <path>] [-c <name>=<value>]
    [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]
    [-p|--paginate|-P|--no-pager] [--no-replace-objects] [--bare]
    [--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]
    [--super-prefix=<path>]
    <command> [<args>]

You can see all the possible switches before <command> [<args>]

--global is a switch for the git config command as seen here, not for "git" alone.

The term "switch" was introduced in commit 0a8365a; May 2005, Git v0.99

diff-tree: fix and extend argument parsing

We use "--" to mark end of command line switches, not "-".

This is inline with the double-hyphen command-line convention, which is, as I explained here, useful if a non-option argument starts with a hyphen.

                       -- optional separator, followed by arguments
                       v
git -p config --global -- user.name
    ^^        ^^^^^^^^
     |            |_ switch for the git config subcommand.
     |
  switch for the git command