On Mon 01 May 2017 at 14:48:13 (-0400), Greg Wooledge wrote: > On Mon, May 01, 2017 at 01:18:58PM -0500, David Wright wrote: > > They do. Both expect a command. You can "show" something but you can't > > "dev" it or, at least, I don't know how to. > > The surprise comes from the fact that typically you can add "dev eth0" > to the end of one working ip command, to get another working ip command > which is restricted to that one interface -- but not always. > > ip addr show (working) > ip addr show dev eth0 (working) > > But > > ip addr (working) > ip addr dev eth0 (NOT working) > > And > > ip -s link show (working) > ip -s link show dev eth0 (working) > > But > > ip -s link (working) > ip -s link dev eth0 (NOT working) > > Apparently, in order to understand why half of the commands work and > half do not, you have to somehow figure out that you're currently using > a command with an assumed verb, and that this makes a difference, in > some way, if you try to add words that follow the assumed verb. Like, > "the verb is only added if the parser runs out of words" or something.
I'd assumed that the presumption of "show [everything]" was there because non-root users can do little else, and I don't think you can omit/assume any other verb. cf mount. > The inconsistency is quite confusing, especially if you haven't > scientifically attempted EVERY combination of words yet, to see which > combinations work and which do not, in order to analyze it for patterns > and infer the actual grammar rules. Sure, but who would prefer "ip link" to give you a load of its BNF rather than assuming you meant show. "ip" does give you BNF, it's true, but with such a flexible command, where to start. "ip nt" already fills the screen; only 16 more object types to go. Cheers, David.
