【已解决】Linux的CentOS 7系统中如何切换用户

【背景】

折腾:

【未解决】Dovecot启动出错:dovecot Fatal Couldn’t parse private ssl_key Expecting ANY PRIVATE KEY

期间,需要去在CentOS 7中切换用户,到root,去执行对应的命令:

/usr/share/doc/dovecot-2.2.10/mkcert.sh

【折腾过程】

1.搜:

linux 切换用户

centos 7 切换用户

centos 7 switch user

参考:

ubuntu linux切换用户到root – 学习记录 – 博客频道 – CSDN.NET

Linux系统中切换用户身份su与sudo的用法与实例 – 斑马Linux – 51CTO技术博客

su – xxx

==su -l xxx

不指定用户,默认为root,所以:

su - 

== su -l

== su -l root

去试试:

crifan@crifan:~$ ll /usr/share/doc/dovecot-2.2.10/
-rw-r--r-- 1 root root     931 Jun 26  2014 mkcert.sh
crifan@crifan:~$ sudo /usr/share/doc/dovecot-2.2.10/mkcert.sh    
sudo: /usr/share/doc/dovecot-2.2.10/mkcert.sh: command not found
crifan@crifan:~$  /usr/share/doc/dovecot-2.2.10/mkcert.sh     
-bash: /usr/share/doc/dovecot-2.2.10/mkcert.sh: Permission denied
crifan@crifan:~$ su -
Password: 
Last login: Sat Aug 15 14:53:40 CST 2015 on pts/1
Last failed login: Sat Aug 15 14:56:40 CST 2015 from 222.186.21.234 on ssh:notty
There were 22 failed login attempts since the last successful login.
[root@crifan ~]# chmod u+x //usr/share/doc/dovecot-2.2.10/mkcert.sh 
[root@crifan ~]# ll //usr/share/doc/dovecot-2.2.10/mkcert.sh          
-rwxr--r-- 1 root root 931 Jun 26  2014 //usr/share/doc/dovecot-2.2.10/mkcert.sh
[root@crifan ~]# ll /usr/share/doc/dovecot-2.2.10/mkcert.sh  
-rwxr--r-- 1 root root 931 Jun 26  2014 /usr/share/doc/dovecot-2.2.10/mkcert.sh
[root@crifan ~]# /usr/share/doc/dovecot-2.2.10/mkcert.sh    
Generating a 1024 bit RSA private key
.........................++++++
........++++++
writing new private key to '/etc/pki/dovecot/private/dovecot.pem'
-----

subject= /OU=IMAP server/CN=imap.example.com/emailAddress=postmaster@example.com
SHA1 Fingerprint=A9:6C:7D:87:90:2F:5A:3C:F3:7A:EB:3D:A8:D4:EE:C6:FD:88:39:39
[root@crifan ~]# su -l crifan
Last login: Sat Aug 15 14:56:32 CST 2015 on pts/1
crifan@crifan:~$ 

2.另外再去试试:

crifan@crifan:~$ su
Password: 
[root@crifan crifan]# pwd
/home/crifan
[root@crifan crifan]# su -l crifan
Last login: Sat Aug 15 14:58:05 CST 2015 on pts/1
crifan@crifan:~$ su -l
Password: 
Last login: Sat Aug 15 15:01:21 CST 2015 on pts/1
[root@crifan ~]# su -l crifan
Last login: Sat Aug 15 15:01:32 CST 2015 on pts/1
crifan@crifan:~$ su -l root
Password: 
Last login: Sat Aug 15 15:01:42 CST 2015 on pts/1
Last failed login: Sat Aug 15 15:02:01 CST 2015 from 222.186.21.234 on ssh:notty
There were 2 failed login attempts since the last successful login.
[root@crifan ~]# su -l crifan
Last login: Sat Aug 15 15:01:53 CST 2015 on pts/1
crifan@crifan:~$ su -
Password: 
Last login: Sat Aug 15 15:02:02 CST 2015 on pts/1
Last failed login: Sat Aug 15 15:02:03 CST 2015 from 222.186.21.234 on ssh:notty
There was 1 failed login attempt since the last successful login.
[root@crifan ~]# su -l crifan
Last login: Sat Aug 15 15:02:12 CST 2015 on pts/1

如图:

switch user su with para and no para of linux

 

【总结】

从普通用户切换到root,算有三种:

  • su
    • 用su登录root后,不知道为何提示符变成了:
    • [root@crifan crifan]#
    • 多了个 crifan,觉得很奇怪,不懂。
  • su –
    • su -和su -l root好像是一样的。
  • su -l root
    • 推荐用此种,最完整的写法:su -l root

 

从root切换到普通用户:

su -l normal_username

比如:

[root@crifan ~]# su -l crifan
Last login: Sat Aug 15 15:01:32 CST 2015 on pts/1


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