knyazuk@knyazuk-Qosmio-X70-A-K2S:~$ sudo adduser --home /home/NewUserCat --disabled-password kobyakin
Adding user `kobyakin' ...
Adding new group `kobyakin' (1001) ...
Adding new user `kobyakin' (1001) with group `kobyakin' ...
Creating home directory `/home/NewUserCat' ...
Copying files from `/etc/skel' ...
Changing the user information for kobyakin
Enter the new value, or press ENTER for the default
	Full Name []:
	Room Number []:
	Work Phone []:
	Home Phone []:
	Other []:
Is the information correct? [Y/n] y
knyazuk@knyazuk-Qosmio-X70-A-K2S:~$ addgroup pibd
addgroup: Only root may add a user or group to the system.
knyazuk@knyazuk-Qosmio-X70-A-K2S:~$ sudo addgroup pibd
Adding group `pibd' (GID 1002) ...
Done.
knyazuk@knyazuk-Qosmio-X70-A-K2S:~$ adduser kobyakin pibd
adduser: Only root may add a user or group to the system.
knyazuk@knyazuk-Qosmio-X70-A-K2S:~$ sudo adduser kobyakin pibd
Adding user `kobyakin' to group `pibd' ...
Adding user kobyakin to group pibd
Done.
knyazuk@knyazuk-Qosmio-X70-A-K2S:~$ su kobyakin
Password:
su: Authentication failure
knyazuk@knyazuk-Qosmio-X70-A-K2S:~$ su kobyakin
Password:
su: Authentication failure
knyazuk@knyazuk-Qosmio-X70-A-K2S:~$ sudo su kobyakin
kobyakin@knyazuk-Qosmio-X70-A-K2S:/home/knyazuk$ pwd
/home/knyazuk
kobyakin@knyazuk-Qosmio-X70-A-K2S:/home/knyazuk$ cd ~/
kobyakin@knyazuk-Qosmio-X70-A-K2S:~$ cd /home/
knyazuk/    NewUserCat/
kobyakin@knyazuk-Qosmio-X70-A-K2S:~$ cd /home/NewUserCat/
kobyakin@knyazuk-Qosmio-X70-A-K2S:~$ ls
kobyakin@knyazuk-Qosmio-X70-A-K2S:~$ mkdir first
kobyakin@knyazuk-Qosmio-X70-A-K2S:~$ cd first/
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first$ mkdir second
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first$ mkdir third
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first$ ls
second  third
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first$ cd second/
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/second$ nano file_1
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/second$ ls
file_1
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/second$ cd ../third/
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third$ mkdir 4
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third$ mkdir 5
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third$ cd 4
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/4$ touch file_2
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/4$ touch file_3
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/4$ cd ../5
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/5$ touch file_4
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/5$ ln
ln: missing file operand
Try 'ln --help' for more information.
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/5$ man ln
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/5$ cd ../4
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/4$ ls
file_2  file_3
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/4$ ln ../../
second/ third/
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/4$ ln ../../second/file_1
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/4$ ls
file_1  file_2  file_3
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/4$ nano file_1
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/4$ man ln
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/4$ ls -L
file_1  file_2  file_3
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/4$ man ln
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/4$ ln file_
file_1  file_2  file_3
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/4$ ln file_3 ../../
second/ third/
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/4$ ln file_3 ../../second/
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/4$ ln file_3 ../
4/ 5/
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/4$ ln file_3 ../5/
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/4$ ls
file_1  file_2  file_3
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/4$ cd ../5/
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/5$ ls
file_3  file_4
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/5$ ls -ali
total 8
526966 drwxrwxr-x 2 kobyakin kobyakin 4096 сен 21 11:21 .
526962 drwxrwxr-x 4 kobyakin kobyakin 4096 сен 21 11:14 ..
527043 -rw-rw-r-- 3 kobyakin kobyakin    0 сен 21 11:14 file_3
526961 -rw-rw-r-- 1 kobyakin kobyakin    0 сен 21 11:15 file_4
kobyakin@knyazuk-Qosmio-X70-A-K2S:~/first/third/5$