[root@redhat ~]# groupadd teachers

[root@redhat ~]# useradd rcwang
[root@redhat ~]# useradd jjli
[root@redhat ~]# useradd hcyang
[root@redhat ~]# useradd ycc

[root@redhat ~]# usermod -aG rcwang teachers
[root@redhat ~]# usermod -aG teachers rcwang
[root@redhat ~]# usermod -aG teachers jjli
[root@redhat ~]# usermod -aG teachers hcyang
[root@redhat ~]# usermod -aG teachers ycc

[root@redhat ~]# fdisk /dev/vdb

Welcome to fdisk (util-linux 2.29.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Device does not contain a recognized partition table.
Created a new DOS disklabel with disk identifier 0x5bb34cbc.

Command (m for help): n
Partition type
   p   primary (0 primary, 0 extended, 4 free)
   e   extended (container for logical partitions)
Select (default p): p
Partition number (1-4, default 1): 1
First sector (2048-20971519, default 2048):
Last sector, +sectors or +size{K,M,G,T,P} (2048-20971519, default 20971519):

Created a new partition 1 of type 'Linux' and of size 10 GiB.

Command (m for help): p
Disk /dev/vdb: 10 GiB, 10737418240 bytes, 20971520 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 8192 bytes
I/O size (minimum/optimal): 8192 bytes / 8192 bytes
Disklabel type: dos
Disk identifier: 0x5bb34cbc

Device      Boot Start      End  Sectors Size Id Type
/dev/vdb1   2048 20971519 20969472  10G 83 Linux

Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

root@ts877:~# mkfs.ext4 /dev/vdb1
mke2fs 1.43.4 (31-Jan-2017)
Discarding device blocks: done
Creating filesystem with 2621184 4k blocks and 655360 inodes
Filesystem UUID: 4fdd9417-445d-4627-b220-9214a2b9c43d
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632

Allocating group tables: done
Writing inode tables: done
Creating journal (16384 blocks): done
Writing superblocks and filesystem accounting information: done

[root@redhat ~]# vim /etc/fstab
/dev/vdb1    /csie    ext4    defaults    0 0


[root@redhat ~]# chmod 774 /csie # 設定權限：rwx rwx r--
[root@redhat ~]# chmod g+s /csie # SetGID 重要!!!!!