Did Sirius have a knife?

[Ersatz Harry]

No: HPFGUIDX 59375

All this talk of Ron's dress robes and the Severing Charm, combined
with some of the recent discussion about WW technology (particularly
plumbing) triggered a thought.  While I don't have PoA with me right
now, I seem to recall that Ron said Sirius had a knife when he
(Sirius) showed up in the dormitory, and that the curtains were
slashed.  I definitely recall that the Fat Lady's painting was
slashed, and I assume that Sirius didn't do that with dog claws since
he had to be in human form to speak the password.  (He could have done
it with a spell, I suppose.)

Doesn't a knife seem to be a bit of a low-tech weapon for the WW?  Am
I recalling Sirius's visit to the dormitory correctly?  Didn't Sirius
have a wand at the Shrieking Shack?

Ersatz Harry