Since first learning Git a few months ago, I've been using git add :/
to stage my files before committing, with the impression that the command stages all modified and newly-added files in my Git directory (I assume I got this impression from one of the articles I was using to learn). This has worked fine for me for the past few months, so at least seems to me to behave that way, but from doing some reading around the answers on this site I get the impression that that isn't the case, and the fact that it's such an under-documented command is another hint to this.
What exactly does git add :/
do? If it doesn't stage all modified and newly-added files, is there a command that does, or is this just not (yet) possible with a single command in Git?