Ok so you're given a Sun Solaris box to test with. You find a bug, you want to raise it - but how do you know what version of Solaris, and what revision exactly is installed?

At the most basic level booting the machine will reveal if you are running Solaris 8, 9 or 10 via a splash screen. However here are some useful commands:

uname -a <-- shows a summary of the system, its name and hardware type, eg:

SunOS Naylor 5.10 Generic_118833-03 sun4u sparc SUNW,Sun-Blade-1000

cat /etc/release <-- shows the exact release of the system, eg:

Solaris 10 1/06 s10s_u1wos_19a SPARC

showrev <-- shows the revision of the hardware and software installed, eg:

Hostname: Naylor
Hostid: 831263df
Release: 5.10 <-- this is the SunOS release which these days corresponds to the Solaris release (.10 = Solaris 10)
Kernel architecture: sun4u
Application architecture: sparc <-- this could also say x86 if not using a SPARC-based box
Hardware provider: Sun_Microsystems
Domain:
Kernel version: SunOS 5.10 Generic_118833-03

showrev -p <-- echos the list of patches applied to a system, which will be quite long.

Therefore:

showrev -p > system.txt

will output the system revision and patchlist to a file you can attach to bug reports if necessary.

Also try:

prtconf -v <-- Displays platform-dependent PROM or booting system version information.
prtconf -p <-- I like to think of this as a summary of the above (it's not quite that but it is easier to digest in a hurry)

If you've used Stop-A you can also:

show-devs <-- outputs the device tree.