O strings /tmp/BE-.../boot/kernel/kernel | egrep ^FreeBSD
resolve seu problema?
uname -v
me fornece o nível de versão do ambiente inicializado.
Como posso obter o nível de versão de um ambiente sem inicializar esse ambiente?
No exemplo abaixo, um ambiente de inicialização (BE) é montado em um caminho temporário pelo TrueOS Desktop. Eu posso acessar partes relevantes do sistema de arquivos, mas não sei onde procurar as informações necessárias:
$ date ; uname -v
Fri 25 Nov 2016 21:15:19 GMT
FreeBSD 12.0-CURRENT #14 1717ae3(drm-next-4.7): Fri Oct 28 13:49:49 UTC 2016 root@gauntlet:/usr/obj/usr/src/sys/GENERIC
$ beadm list
BE Active Mountpoint Space Created Nickname
initial - - 5.4G 2016-08-22 11:24 initial
20161005193649_201610142022 - - 3.1G 2016-10-14 20:22 12.0-CURRENT-up-20161014_204827
20161028134949_201610291803 - - 753.6M 2016-10-29 18:03 12.0-CURRENT-up-20161029_180801
20161028134949_14_201611081710 NR / 45.4G 2016-11-08 17:10 12.0-CURRENT-up-20161108_171012
12.0-CURRENT-up-20161125_173806 - - 7.5G 2016-11-25 17:12 12.0-CURRENT-up-20161125_173806
12.0-CURRENT-up-20161125_201510 - /tmp/BE-12.0-CURRENT-up-20161125_201510.nsZfNFVo 7.4G 2016-11-25 19:49 12.0-CURRENT-up-20161125_201510
$ ls -hl /tmp/BE-12.0-CURRENT-up-20161125_201510.nsZfNFVo
total 215
drwxr-xr-x 2 root wheel 48B 25 Nov 19:56 bin
drwxr-xr-x 10 root wheel 60B 25 Nov 20:15 boot
drwxr-xr-x 3 root wheel 3B 25 Nov 20:02 compat
-r--r--r-- 1 root wheel 6.0K 17 Aug 16:12 COPYRIGHT
dr-xr-xr-x 2 root wheel 3B 22 Aug 11:31 dev
-rw------- 1 root wheel 4.0K 25 Nov 19:48 entropy
drwxr-xr-x 30 root wheel 129B 25 Nov 20:15 etc
lrwxr-xr-x 1 root wheel 9B 22 Aug 11:35 home -> /usr/home
drwxr-xr-x 4 root wheel 59B 25 Nov 19:56 lib
drwxr-xr-x 4 root wheel 6B 25 Nov 19:56 libexec
drwxr-xr-x 2 root wheel 2B 21 Nov 03:14 media
drwxr-xr-x 2 root wheel 2B 8 Oct 12:21 mnt
drwxr-xr-x 2 root wheel 2B 22 Aug 12:05 net
drwxr-xr-x 2 root wheel 2B 22 Aug 11:25 packages
-rw-r--r-- 1 root wheel 21K 25 Nov 20:15 pkg-add.log
dr-xr-xr-x 2 root wheel 2B 17 Aug 16:12 proc
drwxr-xr-x 2 root wheel 146B 25 Nov 19:56 rescue
drwxr-xr-x 10 root wheel 21B 13 Nov 20:13 root
drwxr-xr-x 2 root wheel 146B 25 Nov 19:56 sbin
lrwxr-xr-x 1 root wheel 11B 17 Aug 16:12 sys -> usr/src/sys
drwxr-xr-x 6 root wheel 8B 25 Nov 20:20 tmp
drwxr-xr-x 17 root wheel 17B 22 Aug 11:32 usr
drwxr-xr-x 28 root wheel 30B 25 Nov 20:11 var
$