git two dashes means with no more options

问题:

I am learning the try git by code school, and to the unit 1.17 Undo it use the command line

git checkout -- octocat.txt

and the octocat.txt is a file then and it explain that the two dash lines is

It's simply promising the command line that there are no more options after the '--'. This way if you happen to have a branch named octocat.txt, it will still revert the file, instead of switching to the branch of the same name.

but what I cannot understand is that what does it means by no options? And since there are no options after, why it can distinguish it by file from branch?

回答1:

-- means stop processing options, and even if something does look like an option, e.g. --help, it should be treated as usual parameter, like file name instead.

Using this syntax, you can actually add or remove file which is called say --help, which would be impossible otherwise.

In git syntax, -- is also usually used to specify affected files. For example, git checkout something could mean either checkout branch named something or file called something. If you use git checkout -- something, it always means file, not branch.