There is no one command, "show sysinfo" is an oddball thing specific to the original WLC.To get the equiv on a new controller, you'll need:show versionshow ip int briefsho proc cpu | i CPUsho proc mem | i Poolsho run | i countryshow ap dot11 24ghz su...
That SSH method resets the password, but it leaves it in an expired state, so it's still not useful.I swear the committee of non-technical managers who "trimmed" ISE to make ISE-PIC have never used either product!!