If you issue ls -al /home on a Linux computer as a standard user. You will normally get a list of users on the system.

This is because the permissions to /home/ are 755 which equates to drwxr-xr-x

However if you as root run chmod 751 /home giving permissions of drwxr-x–x a normal user then cannot list the home directories:

ls -al /home/
ls: cannot open directory /home/: Permission denied

Home directory permissions