1.cd / 是跳转到根目录
根目录是所有用户共享的目录
[root@iZuf60zq84uyyxlgy /]# cd /
[root@iZuf60zq84uyyxlgy /]# ll
total 60
lrwxrwxrwx. 1 root root 7 Oct 21 10:28 bin -> usr/bin
dr-xr-xr-x. 5 root root 4096 Oct 21 10:42 boot
drwxr-xr-x 19 root root 2960 Nov 23 17:11 dev
drwxr-xr-x. 76 root root 4096 Nov 24 10:42 etc
drwxr-xr-x. 4 root root 4096 Nov 24 10:13 home
lrwxrwxrwx. 1 root root 7 Oct 21 10:28 lib -> usr/lib
lrwxrwxrwx. 1 root root 9 Oct 21 10:28 lib64 -> usr/lib64
drwx------. 2 root root 16384 Oct 21 10:28 lost+found
drwxr-xr-x. 2 root root 4096 Apr 11 2018 media
drwxr-xr-x. 2 root root 4096 Apr 11 2018 mnt
drwxr-xr-x. 2 root root 4096 Apr 11 2018 opt
dr-xr-xr-x 95 root root 0 Nov 23 17:11 proc
dr-xr-x---. 4 root root 4096 Nov 24 10:42 root
drwxr-xr-x 23 root root 620 Nov 23 17:11 run
lrwxrwxrwx. 1 root root 8 Oct 21 10:28 sbin -> usr/sbin
drwxr-xr-x. 2 root root 4096 Apr 11 2018 srv
dr-xr-xr-x 13 root root 0 Nov 24 09:02 sys
drwxrwxrwt. 8 root root 4096 Nov 24 03:43 tmp
drwxr-xr-x. 13 root root 4096 Oct 21 10:28 usr
drwxr-xr-x. 19 root root 4096 Oct 21 02:33 var
2.cd ~ 是跳转到当前用户的家目录
如果是root用户，cd ~ 相当于 cd /root
[root@iZuf60zq84uyyxlgy13izkZ /]# cd ~
[root@iZuf60zq84uyyxlgy13izkZ ~]# pwd
/root如果是普通用户，cd ~ 相当于cd /home/当前用户名
[chen@iZuf60zq84uyyxlgy13izkZ root]$ cd ~
[chen@iZuf60zq84uyyxlgy13izkZ ~]$ pwd
/home/chen
3.cd /home 相当于查看有多少普通用户的家目录
因为所有的普通用户的父目录都是home目录
[chen@iZuf60zq84uyyxlgy13izkZ home]$ ll
total 8
drwx------ 2 chen chen 4096 Nov 24 10:48 chen
drwx------ 2 hjy hjys1 4096 Nov 24 10:48 hjy