Some linux commands

Linux Version Information

To learn your operating system (OS), and your architecture of  OS
uname
Linux
uname -m
x86_64
Version of the Linux kernel
uname -r
3.10.0-229.el7.x86_64
uname -mrs
Linux 4.2.0-27-generic x86_64
Print all information:
uname -a
Linux *** 4.2.0-27-generic #32~14.04.1-Ubuntu SMP Fri Jan 22 15:32:26 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

To see the Linux distribution name and the version number
cat /etc/*release   or  lsb_release -a
CentOS Linux release 7.1.1503 
cat /proc/version

Linux version 4.2.0-27-generic (buildd@lcy01-23) (gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1) ) #32~14.04.1-Ubuntu SMP Fri Jan 22 15:32:26 UTC 2016

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