The uname shell command will print out in any Debian or RedHat variant like Ubuntu and Centos Linux much of the main system information, here are a few examples below.
Print all system info
uname -a
Linux bitbook-dev 3.13.0-105-generic #152-Ubuntu SMP Fri Dec 2 15:37:11 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
Print Kernel Version
uname -v
#152-Ubuntu SMP Fri Dec 2 15:37:11 UTC 2016
Print OS Version
uname -o
GNU/Linux
Print Release Info
uname -r
3.13.0-105-generic
