Linux Command Line (Practice)

[Case]

Ada company A, memiliki team frontend (Rama, Hanif), backend (Harry, Kacung), dan PM (Josh => memiliki autorisasi ke directory frontend dan backend dan database dan docs) dan masing-masing team di berikan group tersendiri di server.

[Key point]

• Team Frontend yg terdiri dari Rama dan Hanif hanya bisa akses dir frontend dan database aja dan ketika akses dir backend akan permission denied.
• Team Frontend yg terdiri dari Rama dan Hanif hanya bisa akses dir backend dan database aja dan ketika akses dir frontend akan permission denied.
• PM bisa lihat semuanya.
• Semua team bisa akses dir database dan docs.

1. Find and Chose working directory

Find working directory using this command.

$ pwd

Place your working directory in Documents/learn-cli.

# Create dir called learn-cli inside dir Documents 
$ mkdir -p Documents/learn-cli

#  move to learn-cli dir
$ cd Documents/learn-cli

2. Assemble Project Structure

This will be our project dir tree.

learn-cli/
 ├── backend/
 ├── frontend/
 ├── database/
 └── docs/

Utilize this command below to create dirs above.

# Create dirs
$ mkdir backend frontend database docs

# list dir content
$ ls -lah

3. Create Crucial docs

Inside learn-cli/docs create 2 files :

• readme.txt
• features.txt

# Create files
$ touch readme.txt features.txt

# we are inside Documents/learn-cli/docs
$ cp readme.txt ./backend

4. Create Shorcut

Create shortcut from frontend dir to docs

# execute inside learn-cli dir
# we'll create symbolic link
$ ln -s docs docs-shortcut

# verify using list command
$ ls -l

# create hardlink
$ ln docs/readme.txt readme-hardlink.txt

$ ls -li

5. Add new user and group

Groups

• frontend => only accessing frontend dir.
• backend => only accessing backend dir.
• pm => pm (josh) accessing all dirs exclusively.
• shared => accessing docs and database dirs for user frontend and backend, will be linked using ln.
• developer => for accessing main dir in /home/linux/*.

Create group user for all team.

sudo groupadd frontend
sudo groupadd backend
sudo groupadd pm
sudo groupadd shared
sudo groupadd developer

Create user handling group.

# frontend
$ sudo useradd -s /bin/bash -G frontend,shared,developer rama
$ sudo passwd rama

$ sudo useradd -s /bin/bash -G frontend,shared,developer hanif
$ sudo passwd hanif

# backend
$ sudo useradd -s /bin/bash -G backend,shared,developer harry
$ sudo passwd harry

$ sudo useradd -s /bin/bash -G backend,shared,developer kacung
$ sudo passwd kacung

# pm
$ sudo useradd -s /bin/bash -G pm,shared,developer josh
$ sudo passwd josh

Information

You can use these command to listing detailed information about your users.

# list users
cat /etc/passwd | grep username
# or `cut -d: -f1 /etc/passwd`

# list groups
cat /etc/group | grep groupname
# or `cut -d: -f1 /etc/group`

# see user's group
groups username

# detailed user info
id username

# show group info
getent group

6. Secure Ownership Directory

sudo chown root:frontend frontend
sudo chown root:backend backend

set ownership for docs and database dir for being accessed by user groped in shared.

sudo chown root:shared docs
sudo chown root:shared database

Set user linux home directory accessible for other user.

sudo chown root:developer /home/linux

Set group permission

sudo chmod 770 learn-cli/backend 
sudo chmod 770 learn-cli/frontend
sudo chmod 770 learn-cli/docs
sudo chmod 770 learn-cli/database
sudo chmod 770 /home/linux

7. Verify the configuration

Frontend

In this point measure that your main user has grant to group you have created. We will check using first user rama and hanif as frontend. Just hit these command.

Try to switch ro rama user.

su rama

Accessing frontend dir and it must have an access to the dir.

cd /home/linux/Documents/learn-cli/frontend 

If rama user try to access backend dir, it must be permission denied.

cd /home/linux/Documents/learn-cli/backend

Please repeating those but don't forget to switch each user.

Backend

As mentioned that the backend role is filled by harry and kacung so test them using these commands.

su harry

Accessing backend dir and it must have an access to the dir.

cd /home/linux/Documents/learn-cli/backend

If rama user try to access backend dir, it must be permission denied.

cd /home/linux/Documents/learn-cli/frontend 

Please repeating those but don't forget to switch each user.

PM

Project manager or (PM) should have an access to all dirs so make sure that you have given an group access to josh.

su josh

cd /home/linux/Documents/learn-cli/frontend
cd /home/linux/Documents/learn-cli/backend
cd /home/linux/Documents/learn-cli/docs
cd /home/linux/Documents/learn-cli/database