How to output string completions to stdout?

Some of the git commands have many options, and it would often be useful to search through them for the one I need - I was just looking for the option which controls the TAB width in git-gui, but there are about 200 completions for git config. An obvious workaround is to copy all the completions into an editor and search through them, but I'd rather do [something] | grep tab There are no man or info pages for compgen, help compgen doesn't even explain its own options, and there's no auto-complete for compgen (how's that for irony?). PS: compgen -A doesn't work. PPS: This is not a question about git-gui - The solution to the tab width question was elsewhere. PPPS: This is *not* about auto-completing commands, only *command parameters*.