Solaris version numbering

SunOS	Solaris	Flavour
SunOS 4	Solaris 1 (retroactive name)	BSD (Berkeley)
SunOS 5.0	Solaris 2.0	SVR4 (System five)
SunOS 5.1	Solaris 2.1	SVR4 (System five)
…	…	…
SunOS 5.6	Solaris 2.6
SunOS 5.7	Solaris 7
SunOS 5.8	Solaris 8
…	…

To get the SunOS release number:

$ uname –r
5.10
To get the update within a release:

$ cat /etc/release
Solaris 10 5/09 s10s_u7wos_08 SPARC
…
This is Solaris 10 update 7, released 5/2009
Solaris user commands are typically in /usr/bin.
You find other flavours  of these commands (if different) in

• /usr/ucb (Berkeley)
• /usr/xpg4/bin (X/Open Portability Guide v4 compliant)