[root@jeson ~]# chmod u+s /bin/cat
[alice@jeson ~]$ cat /root/install.log

[root@yangs ~]# groupadd sale
[root@yangs ~]# useradd sale01 -G sale
[root@yangs ~]# useradd sale02 -G sale
[root@yangs ~]# id sale01
uid=5006(sale01) gid=5006(sale01) groups=5006(sale01),508(sale)
[root@yangs ~]# id sale02
uid=5007(sale02) gid=5007(sale02) groups=5007(sale02),508(sale)
[root@yangs ~]# mkdir /home/sale
[root@yangs ~]# chgrp sale /home/sale
[root@yangs ~]# chmod 770 /home/sale
[root@yangs ~]# chmod o+t /home/sale
[root@yangs ~]# ll -d /home/sale
drwxrwx--T 2 root sale 409609-0202:26/home/sale

示例3：普通用户启动1024下的端口

Tips:操作系统默认只允许root用户使用1024下的端口。

[root@yangs ~]# chmod 3770 /home/sale
[root@yangs ~]# ll -d /home/sale
drwxrws--T 2 root sale 409609-0202:26/home/sale

[root@jeson ~]# umask //查看当前用户的umask权限0022
[root@jeson ~]# umask -S
u=rwx,g=rx,o=rx

[root@jeson ~]# umask 000	//设置umask权限
[root@jeson ~]# umask 0000
[root@jeson ~]# touch file8	//创建file8文件
[root@jeson ~]# mkdir dir8	//创建目录
[root@jeson ~]# ll -d dir8 file8	//查看文件目录权限
drwxrwxrwx 2 root root 409610-2614:10 dir8
-rw-rw-rw-1 root root    010-2614:10 file8
[root@jeson ~]# umask 022
[root@jeson ~]# umask 0022

[root@jesonc_com ~]# umask 060

[root@jesonc_com ~]# touch file060.txt

[root@jesonc_com ~]# ll file060.txt

-rw----rw- 1 root root 0 10月 29 14:29 file060.txt

[root@jesonc_com ~]# touch file060_2.txt

-rw----rw- 1 root root          0 10月 29 14:30 file060_2.txt

[root@jesonc_com ~]# (umask 060;touch file060_sub.txt)

[root@jesonc_com ~]# ll file060_sub.txt

-rw----rw- 1 root root 0 10月 29 14:31 file060_sub.txt

[root@jesonc_com ~]# touch file060_sub2.txt

[root@jesonc_com ~]# ll file060_sub2.txt

-rw-r--r-- 1 root root 0 10月 29 14:31 file060_sub2.txt