版本号、添加账户密码、切换用户

[[email protected] ~]# cat /etc/redhat-release    版本号查询

CentOS release 6.6 (Final)

[[email protected] ~]# uname -r    内核查询

2.6.32-504.el6.x86_64

[[email protected] ~]# uname -m    32位还是64位

x86_64

[[email protected] ~]# hostname    主机名

wuyike                或：

[[email protected] ~]# uname -n    主机名

wuyike

建立一个新用户：

[[email protected] ~]# useradd keke

[[email protected] ~]# tail -1 /etc/passwd

keke:x:500:500::/home/keke:/bin/bash

[[email protected] ~]# tail -1 /etc/group

keke:x:500:

[[email protected] ~]# tail -1 /etc/shadow

keke:!!:17228:0:99999:7:::

给新用户设置密码：

[[email protected] ~]# passwd keke

查看当前用户：

[[email protected] ~]# whoami

root

[[email protected] ~]$ whoami

keke

提示符@的前面的字符代表当前用户（whoami），后面为主机名（hostname）

Linux命令提示符由PS1环境变量控制：

[[email protected] ~]# echo $PS1

[\[email protected]\h \W]\$

[[email protected] ~]# export PS1="[\[email protected]\h \W \t]\$"

[[email protected] ~ 20:56:05]$

其中PS1="[\[email protected]\h \W \t]\$" 可以通过全局变量配置/etc/profile文件调整。

su与su -

su：用户角色切换，但是环境变量不改变，还是上一个用户的环境变量

su -：用户角色和用户环境变量都切换

从普通用户到root需要输入root密码。从root到普通用户无需密码。

[[email protected] ~]$ env|grep keke

USER=keke

MAIL=/var/spool/mail/keke

PATH=/usr/local/bin:/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/sbin:/home/keke/bin

PWD=/home/keke

HOME=/home/keke

LOGNAME=keke

[[email protected] ~]$ su

Password:

[[email protected] keke]# env|grep keke

USER=keke

PATH=/usr/local/bin:/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/sbin:/home/keke/bin

MAIL=/var/spool/mail/keke

PWD=/home/keke

LOGNAME=keke

[[email protected] keke]# pwd

/home/keke

[[email protected] keke]# env|grep root

HOME=/root

[[email protected] keke]# exit

exit

[[email protected] ~]$ su -

Password:

[[email protected] ~]# env|grep keke

[[email protected] ~]# env|grep root

USER=root

MAIL=/var/spool/mail/root

PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

PWD=/root

HOME=/root

LOGNAME=root