Now let's see how read, write, and execute permissions work on a directory. The easiest example will be the root's home directory /root. Let's do a long listing on /root:
root@ubuntu-linux:~# ls -ld /root
drwx------ 5 root root 4096 Oct 22 14:28 /root
As you can see, full permissions are given to the owner root and zero permissions for everyone else. Let's create a file inside /root named gold:
root@ubuntu-linux:~# touch /root/gold
Now let's switch to user smurf and try to list the contents of the /root directory:
root@ubuntu-linux:~# su - smurf
smurf@ubuntu-linux:~$ ls /root
ls: cannot open directory '/root': Permission denied
User smurf gets a permission denied error as he's got no read permissions on the directory /root. Now, can smurf create a file inside /root?
smurf@ubuntu-linux:~$ touch /root/silver
touch: cannot touch '/root/silver': Permission denied
He cannot since he has no write permissions on /root....
