一、命令

1、增删用户

useradd a1  新建用户a1  cat /etc/passwd  系统保留uid为0-99，0为root,新建用户从500开始

userdel -r  删除用户

usermod -L  锁定用户

usermod -U  解锁

注意：当我们正常通过useradd a1建立用户时（此时没有设置密码,用户a1不能登录系统），我们查看cat /etc/shadow可以看出密码为为 ！，*，x时表示此用户无法登录

[root@localhost tmp]# useradd a1

[root@localhost tmp]# cat /etc/shadow

root:$6$XonOi4Go0YWZh2DD$MhMEqM/mpc7XNcyiYMRdgrP3xOhVanG74LYCAVj1lrCWN9YzQtDvCw3xzdVql..4c10V6YVkjgTr0jlibBQbO1:17122:0:99999:7:::

bin:*:15980:0:99999:7:::

daemon:*:15980:0:99999:7:::

adm:*:15980:0:99999:7:::

lp:*:15980:0:99999:7:::

sync:*:15980:0:99999:7:::

shutdown:*:15980:0:99999:7:::

halt:*:15980:0:99999:7:::

mail:*:15980:0:99999:7:::

uucp:*:15980:0:99999:7:::

operator:*:15980:0:99999:7:::

games:*:15980:0:99999:7:::

gopher:*:15980:0:99999:7:::

ftp:*:15980:0:99999:7:::

nobody:*:15980:0:99999:7:::

dbus:!!:17122::::::

rpc:!!:17122:0:99999:7:::

vcsa:!!:17122::::::

abrt:!!:17122::::::

saslauth:!!:17122::::::

postfix:!!:17122::::::

haldaemon:!!:17122::::::

ntp:!!:17122::::::

apache:!!:17122::::::

rpcuser:!!:17122::::::

nfsnobody:!!:17122::::::

sshd:!!:17122::::::

tcpdump:!!:17122::::::

c2:$6$u0L.la3U$iclu6Lk0YDg93c.g7UdffR88AhoUTq5K/bkjT90MWynj4TsyYh8TdnSKhmyIGQjSRIfY6MwDW6H/azcAyEu3R0:17135:0:99999:7:::

c3:$6$vH1Ki1Gi$Tpmm0RLfYeA/SS3JLg408PWswnQn4vED0Vuz4xVkJ5I6qWg50RrqHk8ixRtSyNJM8bsUtRRL9Bgdof/qmnwBI.:17135:0:99999:7:::

a1:!!:17135:0:99999:7:::

2、组的管理

groupadd -g 1000 market  建立组market,并手动设定GID为1000

groupdel market          删除组market

gpasswd -a a1 market     将用户a1加入组market中

gpasswd -d a1 market     将用户a1从组market中移除

gpasswd -A a1 market     将用户设置为组market的管理员

3、更改文件权限chmod

[root@localhost tmp]# touch test.txt

[root@localhost tmp]# ls -laihs

total 24K

261633 4.0K drwxrwxrwt.  5 root root    4.0K Nov 30 18:35 .

     2 4.0K dr-xr-xr-x. 23 root root    4.0K Nov 17 16:06 ..

266164 4.0K drwxr-xr-x.  2 root root    4.0K Nov 30 15:27 aaa

262057 4.0K -rwxrwx---.  1 root c1group   58 Nov 30 18:18 gongxiang.txt

261872 4.0K drwxrwxrwt.  2 root root    4.0K Nov 17 16:06 .ICE-unix

262063    0 -rw-r--r--.  1 root root       0 Nov 30 18:35 test.txt

261873 4.0K drwxr-xr-x.  5 root root    4.0K Aug 26 05:34 vmware-tools-distrib

[root@localhost tmp]# chmod 775 test.txt 

[root@localhost tmp]# ls -laihs

total 24K

261633 4.0K drwxrwxrwt.  5 root root    4.0K Nov 30 18:35 .

     2 4.0K dr-xr-xr-x. 23 root root    4.0K Nov 17 16:06 ..

266164 4.0K drwxr-xr-x.  2 root root    4.0K Nov 30 15:27 aaa

262057 4.0K -rwxrwx---.  1 root c1group   58 Nov 30 18:18 gongxiang.txt

261872 4.0K drwxrwxrwt.  2 root root    4.0K Nov 17 16:06 .ICE-unix

262063    0 -rwxrwxr-x.  1 root root       0 Nov 30 18:35 test.txt

261873 4.0K drwxr-xr-x.  5 root root    4.0K Aug 26 05:34 vmware-tools-distrib

4、更改文件或目录的属主或属组

 chown :c1group share.txt  将share.txt文件属组改为c1group

 chown c2:c1group 111.txt  将111.txt 文件属主改为c2，属组为c1group

5、setfacl 也可使用acl规则定义

setfacl -m stu:rwx hello_world      让用户stu拥有rwx权限

setfacl -m g:student:rx hello_world 让组student拥有rwx权限

setfacl -x g:student hello_world    解除student组对文件的权限 

本文出自 “小行星” 博客，请务必保留此出处http://3203180.blog.51cto.com/3193180/1878261

第六章 用户及权限管理