查看Linux系统版本

通用方式：

uname -a
cat /proc/version
cat /etc/os-release
通过 dmesg进行过滤，不建议直接使用。常用的linux命令Index of Linux Commands

uname支持不同的参数打印不同的值；uname -a打印所有信息，以下列顺序进行打印，也可以分别指向下列参数获取各自的值

-s内核名称，例如Linux
-n本机名称，例如my-geb
-r内核release版本，例如3.10.0-1127.19.1.el7.x86_64， 5.4.0-48-generic，具体版本可以查看kernel.org
-v内核version，相当于发行日期？例如#1 SMP Wed Sep 26 15:12:11 UTC 2018
-m机器硬件名称，例如x86_64
-p处理器类型，例如x86_64或 unknown
-i硬件平台，例如x86_64或 unknown

#---------------on CentOS
$ uname -a
Linux g1-qa-biggrok-01 3.10.0-1127.19.1.el7.x86_64 #1 SMP Tue Aug 25 17:23:54 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

$ cat /proc/version
Linux version 3.10.0-1127.19.1.el7.x86_64 (mockbuild@kbuilder.bsys.centos.org) (gcc version 4.8.5 20150623 (Red Hat 4.8.5-39) (GCC) ) #1 SMP Tue Aug 25 17:23:54 UTC 2020

$ cat /etc/os-release
NAME="CentOS Linux"
VERSION="7 (Core)"
ID="centos"
ID_LIKE="rhel fedora"
VERSION_ID="7"
PRETTY_NAME="CentOS Linux 7 (Core)"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:centos:centos:7"
HOME_URL="https://www.centos.org/"
BUG_REPORT_URL="https://bugs.centos.org/"

CENTOS_MANTISBT_PROJECT="CentOS-7"
CENTOS_MANTISBT_PROJECT_VERSION="7"
REDHAT_SUPPORT_PRODUCT="centos"
REDHAT_SUPPORT_PRODUCT_VERSION="7"

#---------------on Ubuntu

~ uname -a
Linux guazistf 5.4.0-48-generic #52~18.04.1-Ubuntu SMP Thu Sep 10 12:50:22 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

~ cat /proc/version
Linux version 5.4.0-48-generic (buildd@lcy01-amd64-023) (gcc version 7.5.0 (Ubuntu 7.5.0-3ubuntu1~18.04)) #52~18.04.1-Ubuntu SMP Thu Sep 10 12:50:22 UTC 2020

~ cat /etc/os-release
NAME="Ubuntu"
VERSION="18.04.3 LTS (Bionic Beaver)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 18.04.3 LTS"
VERSION_ID="18.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=bionic
UBUNTU_CODENAME=bionic

个性方式：
ubuntu：lsb_release -a
centOS： hostnamectl

# on Ubuntu 
> lsb_release -a
LSB Version:    core-9.20170808ubuntu1-noarch:security-9.20170808ubuntu1-noarch
Distributor ID: Ubuntu
Description:    Ubuntu 18.04.3 LTS
Release:        18.04
Codename:       bionic

# on CentOS 
> hostnamectl
   Static hostname: g1-qa-biggrok-01
         Icon name: computer-server
           Chassis: server
        Machine ID: e5783e20f48c4e709dc17d6065f51055
           Boot ID: ec31320477044fc1b8d19aa1883ff3e3
  Operating System: CentOS Linux 7 (Core)
       CPE OS Name: cpe:/o:centos:centos:7
            Kernel: Linux 3.10.0-1127.19.1.el7.x86_64
      Architecture: x86-64

CentOS 7 vs CentOS 8 – Feature Comparison

内核版本(Kernel Version:)

[CentOS6] 2.6.x-x
[CentOS7] 3.10.x-x
[CentOS8] 4.18.0-x