This short tutorial by user Vivek Gite (nixCraft) shows us how to figure out your FreeBSD version and patch level number.

Original: http://www.cyberciti.biz/faq/how-to-find-out-freebsd-version-and-patch-level-number/

How do I find out my FreeBSD server version and patch level of the installed system using command line option?

Tutorial details
Difficulty Easy (rss)
Root privileges No
Requirements None
Estimated completion time 1m

You can use any one of the following command to display the FreeBSD operating system version and patch level:a) freebsd-version command – Show the version and patch level of the installed system

b) uname command – Show information about the system

Say hello to freebsd-version command

The freebsd-version command appeared in FreeBSD version 10.0. To see the version and patch level of the installed kernel:
freebsd-verion -k
To see the version and patch level of the installed userland:
freebsd-verion -u
Sample outputs:

Fig.01: freebsd-version and other commands in action
(Fig.01: freebsd-version and other commands in action)

You can see a system being repaired using a live CD:
mount -rt ufs /dev/ada0p2 /mnt
env ROOT=/mnt /mnt/bin/freebsd-version -ku

You can also use the following command to find out if FreeBSD kernel is running in 32bit or 64bit mode:
# getconf LONG_BIT

Sample outputs:
64

Old good uname command

Type the following command (it works on all versions of FreeBSD):
umame -a
uname -mrs

Outputs:
FreeBSD 10.1-RELEASE-p10 amd64