The Pi is installed now what do we do?

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Make user accounts, file permissions, install a webserver

Users & Groups

Making a new user on the Pi

sudo adduser USERNAME

Add this user to the sudo group

sudo addgroup USERNAME GROUPNAME
sudo addgroup USERNAME sudo

Logout of the current ssh connection

exit

Now log in with your new user

ssh user@ipadress

Try to see if your sudo powers work

sudo test

Let's remove the user "pi".
It's not safe to keep the default user and password logins enabled.
Note! This means that you can only login with the useraccount you just made, so don't loose your password!

sudo deluser pi

If it does not work, it could be that the user pi is still being used. Try to reboot the pi and do it again.

sudo reboot
ssh USERNAME@ip-adress
sudo deluser pi

Change the hostname of the Pi

You can change this name, by editing these two files:

sudo nano /etc/hostname
sudo nano /etc/hosts

Change /etc/hosts into:

127.0.0.1    localhost
::1    localhost ip6-localhost ip6-loopback
ff02::1   ip6-allnodes
ff02::2   ip6-allrouters

127.0.1.1    newhostname (needs to be the same as your hostname)

The hostname will be changed after a reboot.

So reboot and ssh in again.

sudo reboot
ssh USERNAME@ip-address

or

ssh USERNAME@HOSTNAME.local

Install a webserver

So we can host webpages on our Pi, that can be reached when we type the ip-address in the browser.

sudo apt install nginx

Once it's done, let's go to the folder that nginx uses to serve files from:

cd /var/www/html/

And try to check if nginx serves you a file in the browser, by visiting the ip address of your pi, for example:

145.24.131.184

To edit this page, remove the standard index file and make a new index.html file

rm /var/www/html/index.nginx-debian.html
nano /var/www/html/index.html

You might get a permission denied error now.....

This is because the /var/www/html/ is not configured with the right permissions.

Let's make a group for all the users on this pi,
we will give this group the permissions to write in this folder.

sudo addgroup USERNAME users

File Permissions

Let's take a look at file permissions How do you know the permission settings of a file? And how do you change them?

(This is documented here too: https://pzwiki.wdka.nl/mediadesign/Shell_Cheat_Sheet#File_Permissions )

ls -la

Outputs:

total 24
drwxr-xr-x 3 flo  flo  4096 Mar  4 16:03 .
drwxr-xr-x 6 root root 4096 Mar  4 15:41 ..
-rw-r--r-- 1 flo  flo   220 Mar  4 15:41 .bash_logout
-rw-r--r-- 1 flo  flo  3523 Mar  4 15:41 .bashrc
drwx------ 3 flo  flo  4096 Mar  4 16:03 .gnupg
-rw-r--r-- 1 flo  flo   807 Mar  4 15:41 .profile

Let's unpack this!

d = directory
rwx rwx rwx
U   G   O
u = user
g = group
o = other
user has the permission to: rwx (read, write, execute)
group has the permission to: r-x (read, execute)
other has the permission to: r-x (read, execute)

Two programs can be used to change ownership and permissions:

chown = change ownership     (Ownership is split up in a user and a group)
chmod = change modes         (Modes are the filesystem permissions given to user, group and others classes to access files under Unix.)

To see the permissions of the /var/www/html folder

ls -l /var/www/

Outputs:

total 12
drwxr-xr-x  3 root root 4096 Mar  4 15:57 .
drwxr-xr-x 12 root root 4096 Mar  4 15:57 ..
drwxr-xr-x  2 root root 4096 Mar  4 15:58 html

Let's unpack this again!

d rwx r-x r-x 
  U   G   O
U = rwx
G = r-x
O = r-x
owned by user: root
owned by group: root

We want to change the permissions and ownership to:

user: root      (or anything else)
group: users    (this is the shared group that we just made)
G = rwx         (read, write and execute permissions)

To change ownership to user=root and group=users:

chown -R root:users /var/www/html/

To change permissions of group:

chmod -R g+w /var/www/html/

Check if it worked:

ls -l

And try to edit the index.html file now in /var/www/html/

nano /var/www/html/index.html