1. 查看centos内核的版本：
1)
[root@localhost ~]# cat /proc/version
Linux version 2.6.18-194.el5 (mockbuild@builder10.centos.org) (gcc version 4.1.2 20080704 (Red Hat 4.1.2-48)) #1 SMP Fri Apr 2 14:58:14 EDT 2010
2)
[root@localhost ~]# uname -a
Linux localhost.localdomain 2.6.18-194.el5 #1 SMP Fri Apr 2 14:58:14 EDT 2010 x86_64 x86_64 x86_64 GNU/Linux
3)
[root@localhost ~]# uname -r
2.6.18-194.el5

2. 查看linux版本：
1) 列出所有版本信息,
[root@localhost ~]# lsb_release -a
LSB Version: :core-3.1-amd64:core-3.1-ia32:core-3.1-noarch:graphics-3.1-amd64:graphics-3.1-ia32:graphics-3.1-noarch
Distributor ID: CentOS
Description: CentOS release 5.5 (Final)
Release: 5.5
Codename: Final
注:这个命令适用于所有的linux，包括Redhat、SuSE、Debian等发行版。
2) 执行cat /etc/issue,例如如下:
[root@localhost ~]# cat /etc/issue
CentOS release 5.5 (Final)
Kernel r on an m
3) 执行cat /etc/redhat-release ,例如如下:
[root@localhost ~]# cat /etc/redhat-release
CentOS release 5.5 (Final)

3. 查看系统是64位还是32位：
1、getconf LONG_BIT or getconf WORD_BIT
[root@localhost ~]# getconf LONG_BIT
64
2、file /bin/ls
[root@localhost ~]# file /bin/ls
/bin/ls: ELF 64-bit LSB executable, AMD x86-64, version 1 (SYSV), for GNU/Linux 2.6.9, dynamically linked (uses shared libs), for GNU/Linux 2.6.9, stripped
3、lsb_release -a
[root@localhost ~]# lsb_release -a
LSB Version: :core-3.1-amd64:core-3.1-ia32:core-3.1-noarch:graphics-3.1-amd64:graphics-3.1-ia32:graphics-3.1-noarch
Distributor ID: CentOS
Description: CentOS release 5.5 (Final)
Release: 5.5
Codename: Final