Tag: howto

Install and configure SSH on Debian or Ubuntu

SSH is a protocol that enables secure connections over unsecured networks. It supports the use of asymmetric encryption for user authentication. Private keys are kept locally, while public keys are stored on the remote machine.

The following configuration disables root logins on the remote machine. Only users belonging to the group ssh-users may establish a connection. Access to the remote machine is tied to the local user’s private key.

In this example, the name of the remote machine is debian-server, which has the address 192.168.1.10 on the network. sid is a user on debian-server, whereas bookworm is a user on the local machine. Choose an encryption passphrase to secure the private key that you will generate in Step 5.

On the remote machine

Step 1

Install the secure shell server with the following command:

$ sudo apt install --yes openssh-server

Step 2

If you are using ufw as a host-based firewall

Configure ufw to allow connections to the secure shell server.

$ sudo ufw limit ssh

If you are using firewalld as a host-based firewall

Configure firewalld to allow connections to the secure shell server.

$ sudo -- bash -c 'firewall-cmd --zone=public --add-service=ssh --permanent && firewall-cmd --reload && firewall-cmd --info-zone=public'

Step 3

Restrict access to the remote machine to members of a specific group. Start by creating the group ssh-users.

$ sudo addgroup --system ssh-users

Add the user sid to the group ssh-users.

$ sudo adduser sid ssh-users

On the local machine

Step 4

Install the secure shell client with the following command.

$ sudo apt install openssh-client

Step 5

Generate a new key pair for the local user bookworm:

$ ssh-keygen -t ed25519 -o -a 100

Save the key pair to the directory /home/bookworm/.ssh/. Choose a name that facilitates easy identification.

Enter file in which to save the key (/home/bookworm/.ssh/id_ed25519): ~/.ssh/id_ed25519-debian-server

The use of an appropriate passphrase to secure the private key is mandatory.

Step 6

Create the file ~/.ssh/config to configure the secure shell client.

$ nano ~/.ssh/config

Add the follwing minimal entry for the host debian-server.

Host debian-server
   Hostname 192.168.1.10
   IdentitiesOnly yes

Step 7

Deploy the public key with the following command.

$ ssh-copy-id -i ~/.ssh/id_ed25519-debian-server.pub sid@debian-server

Step 8

Log into the remote machine.

$ ssh -i ~/.ssh/id_ed25519-debian-server sid@debian-server

When prompted to confirm the authenticity of the host debian-server, type yes and press [Enter].

The authenticity of host 'debian-server (192.168.1.10)' can't be established.
ED25519 key fingerprint is SHA256:C9RxLLVbvFwVJc0L4JHzcuHQSaPHJZe/GrRDvqy6rAG.
This key is not known by any other names.
Are you sure you want to continue connecting (yes/no/[fingerprint])?

In the next step, enter the passphrase for your private key.

Enter passphrase for key '/home/bookworm/.ssh/id_ed25519-debian-server':

Step 9

On the remote machine, download a file to harden the ssh server. You are encouraged to inspect its contents.

$ sudo -- bash -c 'wget -P /etc/ssh/sshd_config.d/ --show-progress https://edafe.de/debian/sshd_config.conf'

Activate the modifications on the remote machine.

$ sudo systemctl restart ssh.service

Step 9

On the local machine, open a new terminal window and run the following command.

$ $ ssh -i ~/.ssh/id_ed25519-debian-server sid@debian-server

In the next step, enter the passphrase for your private key.

Enter passphrase for key '/home/bookworm/.ssh/id_ed25519-debian-server':

Display the active configuration for the remote ssh server and verify its settings, paying particular attention to options for maxauthtries, permitrootlogin and passwordauthentication.

$ sudo sshd -T

All done!

For more in-depth information, please see stribika’s post-Snowden advice on hardening OpenSSH server installations.

The book SSH The Secure Shell by Daniel Barrett, Richard Silverman and Robert Byrnes is still useful today and has information on other clever stuff you can do with SSH.

Install OneDrive Client for Linux on Debian or Ubuntu

The OneDrive Client for Linux connects your Debian or Ubuntu system to Microsoft’s OneDrive Personal, OneDrive for Business, OneDrive for Office365, Sharepoint and other such deployments.

Step 1

Install the OneDrive Client from the Debian or Ubuntu repository.

$ sudo -- bash -c 'apt update && apt install --yes onedrive'

Step 2

Begin to connect the client to your OneDrive account.

$ onedrive --synchronize

You will be presented with a message similar to the following:

Configuring Global Azure AD endpoints
Authorize this app visiting:

https://login.microsoftonline.com/common/oauth2/v2.0/authorize?client_id&scope=Files.ReadWrite%20Files.ReadWrite.all%20Sites.Read.All%Sites.ReadWrite.All%20offline_accessresponse_type=code&redirect_uri=https://login.microsoftonline.com/common/oauth2/nativeclient

Enter the response uri:

In the above dialog, copy or [Ctrl + Click] the URI beginning with https://login.microsoftonline.com/.

In a web browser

Use the URI from the previous step to sign into your Microsoft account. You will be redirected to a response URI displaying a blank page. Copy the response URI from the address field of your browser.

In the terminal

Paste the response URI into the terminal. On successful authentication, the OneDrive Client will connect to your Microsoft account and begin to download your data.

Initializing the Synchronization Engine …
Syncing changes from OneDrive …
Creating local directory:
Downloading file … done.
Uploading differences of ~/OneDrive
Uploading new items of ~/OneDrive

Step 3

After downloading your data to ~/OneDrive, validate the configuration of the client.

$ onedrive --display-config

If required, you may change the default configuration.

Step 4

Enable OneDrive Client for the local user bookworm.

$ sudo -- bash -c 'systemctl enable onedrive@bookworm.service && systemctl start onedrive@bookworm.service && systemctl status onedrive@bookworm.service'

All done!

How to install Espanso from source on Debian 12 Bookworm

Currently available Espanso packages fail to install on Debian 12 because of unmet dependencies. Given that I depend on Espanso to expand text shortcuts and insert special characters, I was stuck on Debian 11. Until now!

The following instructions have also been tested with Debian 11.

After completing the installation, Espanso 2.2.0 for Wayland will be installed on your system and enabled for the current user.

Compiling Espanso from source code

Side-step any dependency problems by compliling Espanso from source and moving the binary into place.

Step 1

Install the required C/C++ compiler and some additional tools.

$ sudo apt-get install --yes build-essential curl git wl-clipboard libxkbcommon-dev libdbus-1-dev libwxgtk3.*-dev libssl-dev

Step 2

Install the required Rust compiler, which is managed by the rustup tool.

$ curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh&&source ~/.bashrc

Press [Enter] to proceed with the installation.

Current installation options:

1) Proceed with instalation (default)
2) Customize installation
3) Cancel installation
>

Install cargo-make, which is required during the build process.

$ cargo install --force cargo-make

Step 3

Get the source code by cloning the Espanso repository to the local directory ~/.local/src/espanso.

$ git clone --progress https://github.com/federico-terzi/espanso ~/.local/src/espanso

Step 4

Compile the Espanso binary in release mode and as a Wayland-only build.

$ cargo make --cwd ~/.local/src/espanso --profile release --env NO_X11=true build-binary

Move the binary to the /usr/local/bin directory.

$ sudo mv ~/.local/src/espanso/target/release/espanso /usr/local/bin/

Step 5

Give Espanso the permissions it requires for operation.

$ sudo setcap "cap_dac_override+p" $(which espanso)

Check to see if the Espanso binary was installed successfuly.

$ espanso --version

Step 6

Integrate Espanso into the system by registering it as a systemd service.

$ espanso service register

Start Espanso.

$ espanso start&& espanso status

Step 7

In GNOME, remove the conflicting default shortcut for activating the window menu.

Settings > Keyboard > Keyboard Shortcuts > View and Customize Shortcuts > Windows > Activate the window menu > [Backspace]

From now on, use [Alt + Space] to open Espanso’s Search bar.

All Done!

Please keep in mind that Wayland support at this point has some known limitations. Most notably, “there is currently no support for App-specific configurations“.

Big thank you to Federico Terzi for creating such a useful tool for us all to use!

Install and configure nullmailer using Fastmail as a smarthost

If you want to receive status updates from your Debian or Ubuntu system in your inbox, you need to employ the help of a mail tansfer agent (MTA). nullmailer is a relay-only forwarding MTA that can be used as an alternative to more complex MTAs such as Exim, Sendmail or Postfix. Instructions for setting up Exim are available for comparison.

nullmailer can be configured to use Fastmail as a smarthost and hence ensure the deliverability of your messages. In principle, these instructions should also be applicable to service providers other than Fastmail.

In the following example configuration, debian is the hostname, bookworm the local username and linus.torvalds@fastmail.com the Fastmail username.

Step 1

Log into your Fastmail account and set up a new app password for SMTP authentication.

Step 2

Create the new directory /etc/nullmailer and the file /etc/nullmailer/adminaddr.

$ sudo mkdir /etc/nullmailer && sudo nano /etc/nullmailer/adminaddr

Your Fastmail username is the only entry in /etc/nullmailer/adminaddr.

linus.torvalds@fastmail.com

Step 3

Install the required packages.

$ sudo apt-get install --yes nullmailer mailutils

Step 4

Perform the initial configuration using debconf. Reconfigure nullmailer at any time after the initial installation using the following comand.

$ sudo dpkg-reconfigure nullmailer

Setting the mail name

Set the system mail name. If you are setting up on a home network, you should use home.arpa as the domain name.

Configuring nullmailer

Mailname of your system:

debian.home.arpa

Ok

Configuring the smarthost

Set the Fastmail server as the smarthost. Use the app password you set in Step 1.

Configuring nullmailer

Smarthosts:

smtp.fastmail.com smtp --port=587 --auth-login --starttls --user=linus.torvalds@fastmail.com --pass=password

Ok

Step 5

Test your configuration with the following command.

echo "Test mail from nullmailer on debian.home.arpa to the local root user and forwarded on to Fastmail" | mail -s "Test nullmailer" root

Check your Inbox, Linus!

Install Syncthing for continuous file synchronisation on Debian or Ubuntu

Syncthing is an open source tool that synchronises data across multiple devices. It transfers your files peer-to-peer, without the requirement to upload your information to the cloud. Packages are available for Android, Windows, macOS and Linux (including Synology DSM).

The usefulness of this project cannot be overstated.

Running the Syncthing stable channel

Syncthing is included in the Debian and Ubuntu repositories, respectively. These instructions are targeting the latest release of the Syncthing stable channel. It is therefore necessary to add the Syncthing repository to your list of APT sources.

In the following example, bookworm is the local username.

Step 1

Add the Syncthing release key for validation of packages downloaded from the Syncthing repository.

$ sudo curl -o /usr/share/keyrings/syncthing-archive-keyring.gpg https://syncthing.net/release-key.gpg

Step 2

Add the Syncthing repository.

$ echo "deb [signed-by=/usr/share/keyrings/syncthing-archive-keyring.gpg] https://apt.syncthing.net/ syncthing stable" | sudo tee /etc/apt/sources.list.d/syncthing.list

Step 3

Install Syncthing on your system.

$ sudo -- bash -c 'apt update && apt install --yes syncthing apt-transport-https'

Step 4

Enable Syncthing for the local user bookworm.

$ sudo -- bash -c 'systemctl enable syncthing@bookworm.service && systemctl start syncthing@bookworm.service && systemctl status syncthing@bookworm.service'

Step 5

You may need to edit your firewall settings to open ports for incoming and outgoing traffic.

If you are using ufw as a host-based firewall

Configure ufw to allow connections to Syncthing.

$ sudo ufw limit syncthing

If you are using firewalld as a host-based firewall

Configure firewalld to allow connections to Syncthing.

$ sudo -- bash -c 'firewall-cmd --zone=public --add-service=syncthing --permanent && firewall-cmd --reload && firewall-cmd --info-zone=public'

Step 6

Access the Syncthing configuration page by using your browser to navigate to the following address:

http://localhost:8384

Step 7

Complete your setup by referring to the Syncthing documentation.

Install Cockpit on Debian 12 Bookworm

Cockpit is a web-based management tool for Linux systems. It aims to simplify management tasks while maintaining compatibility with other administration tools.

Step 1

Cockpit requires the use of the firewalld service to be able to make changes to your firewall rules.

If you are using ufw as a host-based firewall

Remove ufw before replacing it with firewalld.

$ sudo apt-get remove --purge --yes ufw

Install firewalld as a host-based firewall

Install firewalld and maintain ssh access as well as enabling cockpit to receive incoming connections.

$ sudo -- bash -c 'apt-get install --show-progress --yes firewalld && systemctl enable --now firewalld.service && firewall-cmd --zone=public --add-service=ssh --permanent && firewall-cmd --zone=public --add-service=cockpit --permanent && firewall-cmd --reload && firewall-cmd --info-zone=public'

Step 2

Proceed to install Cockpit and selected add-on applications.

$ sudo apt-get install --show-progress --yes cockpit cockpit-machines cockpit-pcp nullmailer ssh tuned-utils

Step 3

By default, the Cockpit web console listens on port 9090 for connections. If you want to make changes from the default, use the following command to edit /etc/systemd/system/cockpit.socket.d/override.conf.

$ sudo systemctl edit cockpit.socket

The example below changes the web console port from 9090 to 9091 and restricts access to the localhost.

### Editing /etc/systemd/system/cockpit.socket.d/override.conf
### Anything between here and the comment below will become the new contents of the file

[Socket]
ListenStream=
ListenStream=127.0.0.1:9091

### Lines below this comment will be discarded

Use the following command for your changes to take effect.

$ sudo -- bash -c 'systemctl daemon-reload && systemctl restart cockpit.socket && systemctl status cockpit.socket'

Step 4

If you installed Cockpit on the local machine and changed the listening port to 9091, you can now access the Cockpit web console on https://localhost:9091.

How to install Debian 12 Bookworm with a GNOME desktop

Debian GNU/Linux was first released in 1993 and has been under active developement ever since. Today, the Debian Project unites thousands of contributors from across the globe with the aim of producing “an operating system distribution that is composed entirely of free software”.

This guide is intended to assist those who are installing Debian for the first time. It describes a straightforward path to a GNOME desktop. The number of applications is less in comparison to the default. Choose from more than 60000 official packages to tailor the system to your own requirements.

Debian and the new package formats

Debian stable is, above all else, focused on the task of maintaining bug-free software packages. It is the reason why Debian, in over 30 years, has gained a reputation for being “like a rock in an ever-swirling sea of updates”. It is also the reason why Debian stable does not keep up with the latest versions.

Universal package formats, such as Flatpak, Snap or AppImage, are managed separately from conventional packaging systems and thus provide the end-user with added flexibility and choice. They solve the problem of stale distribution packages because newer versions can be installed without compromising the integrity of the underlying core.

Before you begin

In addition to the target computer, you should have access to a reasonably fast connection to the Internet. Ideally, your device would connect to your router by Ethernet cable. If your laptop does not have an Ethernet port, consider using the Plugable USB 3.0 Gigabit Ethernet Adapter.

Use Etcher to flash a bootable Debian CD image to a USB drive. Alternatively, you may wish to install Ventoy and boot directly from the image file.

Depending on your acutal requirements, there are different Debian CD images to choose from. In all likelihood, you are following these instructions to install on x86-64 hardware, for which a network install CD image amd64 would be the correct choice. It supports Intel as well as AMD processors and “includes non-free firmware for extra support for some awkward hardware”.

Choose a hostname and a username for your setup. In the examples which follow, debian is used as the hostname and bookworm as the username. Just remember to make the substitutions when executing commands that reference either.

Choose 1) an encryption passphrase to encrypt your storage device, 2) a user password to secure your user account, and 3) a root password to secure the root account.

Ensure that all of your data is safely backed up because formatting your storage device will erase all of its data.

After completing the installation, Debian GNU/Linux will be the only operating system on your computer.

Installing Debian GNU/Linux

If your computer uses the Unified Extensible Firmware Interface (UEFI) and you are unsure about which settings to use, you may wish to disable the Secure Boot option.

Step 1

After booting the system from the USB stick that you have prepared, continue by selecting the text based installer.

Step 2

Keep English as the language for the installation.

[!!] Select a language

Language: English

Step 3

Keep United States as the location for your system. This will also set United States as the default locale for the system environment. You will have an opportunity to set additional locales and adjust time zones at a later point during the installation.

[!!] Select your location

Country, territory or area: United States

Step 4

Use the keymap that is the correct one for your particular keyboard.

[!!] Configure the keyboard

Keymap to use: your keyboard

Step 5

You will likely be asked to select the primary network interface for use during the installation. If network autoconfiguration fails, go back to try another network interface from the list.

[!!] Configure the network

Network configuration method:

Retry network autoconfiguration
Retry network autoconfiguration with a DHCP hostname
Configure network manually

Do not configure the network at this time

Go Back

Step 6

Set the hostname for your system. In this example, we use debian as the hostname.

[!] Configure the network

Hostname: debian

Continue

Set the domain name for your system. If you are setting up on a home network, you should use home.arpa as the domain name.

[!] Configure the network

Domain name: home.arpa

Continue

Step 7

Leave the root password empty to ensure the standard user account will automatically be configured with sudo privileges.

[!!] Set up users and passwords

Root password: leave empty

Continue

Confirm the empty root password.

[!!] Set up users and passwords

Re-enter password to verify: leave empty

Continue

Create the standard user. In this example, we use Bookworm as the full name.

[!!] Set up users and passwords

Full name for the new user: Bookworm

Continue

Your username should start with a lower-case letter. In this example, bookworm is a reasonable choice.

[!!] Set up users and passwords

Username for your account: bookworm

Continue

Set a password for the new standard user.

[!!] Set up users and passwords

Choose a password for the new user: your user password

Continue

Confirm the password for the new standard user.

[!!] Set up users and passwords

Re-enter password to verify: your user password

Continue

Keep Eastern as the time zone for now.

[!] Configure the clock

Select your time zone: Eastern

Step 8

You may wish to partition your disk with LVM and protect your data with a 256 bit AES key.

[!!] Partition disks

Partitioning method: Guided - use entire disk and set up encrypted LVM

Be careful to select the correct target device for your system.

[!!] Partition disks

Select disk to partition: your target disk for installation

Choose to keep all files in one partition.

[!] Partition disks

Partitioning scheme: All files in one partition (recommended for new users)

Now write the changes to disk.

[!!] Partition disks

Write the changes to disk and configure LVM?

Yes

You may skip the overwriting of the disk with random data by selecting Cancel. Be aware, however, that skipping this step will lessen the quality of the encryption.

Step 9

Enter your encryption passphrase.

[!!] Partition disks

Encryption passphrase: your encryption passphrase

Continue

Confirm your encryption passphrase.

[!!] Partition disks

Re-enter passphrase to verify: your encryption passphrase

Continue

Step 10

Use the available space for partitioning your disk.

[!!] Partition disks

Amount of volume group to use for guided partitioning: max

Continue

Step 11

Write the changes to disk.

[!!] Partition disks

Finish partitioning and write changes to disk

Confirm writing the changes to disk.

[!!] Partition disks

Write the changes to disks?

Yes

Step 12

You may be asked to scan additional installation media.

[!] Configure the package manager

Scan extra installation media?

No

Step 13

Select your archive mirror country from the list.

[!] Configure the package manager

Debian  archive mirror country: your country

Select an archive mirror from the list. For the fastest downloads, use the site that is closest to you.

[!] Configure the package manager

Debian archive mirror: mirror closest to you

You probably won’t need to configure an HTTP proxy:

[!] Configure the package manager

HTTP proxy information (blank for none): leave empty

Continue

Step 14

The Debian Popularity Contest attempts to map the overall usage of Debian packages with information from installed systems, such as yours.

[!] Configuring popularity-contest

Participate in the package usage survey?

Yes

Step 15

Choose standard system utilities from the list of predefined software collections and deselect all other entries.

[!] Software selection

Choose software to install:
[ ] Debian desktop environment
[ ] GNOME
[*] standard system utilities

Continue

Step 16

You may be asked if you want to install the GRUB boot loader to your primary drive. Select your target disk from Step 8 as the drive for boot loader installation.

[!] Install the GRUB boot loader

Install the GRUB boot loader to your primary drive?

Yes

Step 17

Remove the installation media before booting into your new system.

[!!] Finish the installation

Installation complete

Continue

Step 18

Enter your encryption passphrase to boot into the system for the first time. In this example, the encrypted disk is labelled sda3_crypt.

Please unlock disk sda3_crypt: your encryption passphrase

Log into the system with your username and user password.

Debian GNU/Linux 12 debian tty1

debian login: bookworm
Password: your user password

Step 19

Set the password for the root user by entering the following command. You will be asked for your user password to obtain sudo privileges first.

$ sudo passwd root

Step 20

Install a minimal GNOME desktop.

$ sudo apt-get install --yes gnome-core

If you are installing into a virtual machine, use this additional command to enable copy and paste between the host and the guest.

$ sudo apt-get install --yes spice-vdagent

Step 22

Restart your system.

$ sudo reboot

Step 23

Enter your encryption passphrase to boot into the system.

Please unlock disk sda3_crypt: your encryption passphrase

Log into the GNOME desktop environment.

Step 24

Select Show Applications from the the panel at the bottom of the screen or press [Super + a] and open the Settings application. On most keyboards, the [Super] key is the one with the Windows logo printed on it. Continue by adding the following keyboard shortcuts:

Terminal application

Settings > Keyboard > Keyboard Shortcuts > View and Customize Shortcuts > Custom Shortcuts > Add Shortcuts
Name: Launch Terminal

Command: gnome-terminal

Shortcut: [Super + t]

File manager

Settings > Keyboard > Keyboard Shortcuts > View and Customize Shortcuts: Home folder
Shortcut: [Super + f]

Web browser

Settings > Keyboard > Keyboard Shortcuts > View and Customize Shortcuts: Launch web browser
Shortcut: [Super + b]

Maximising windows vertically

Settings > Keyboard > Keyboard Shortcuts > View and Customize Shortcuts: Maximize window vertically
Shortcut: [Ctrl + Super + ↑]

Step 25

From within the GNOME desktop, open Firefox ESR by using the shortcut [Super + b] and re-open these instructions at edafe.de/step25.

Open a terminal with the shortcut [Super + t] and, where applicable, use copy and paste to enter the commands set out on this page. Be careful not to miss any punctuation.

Step 26

Set the time zone for your area.

$ sudo dpkg-reconfigure tzdata
Configuring tzdata

Geographic area: your area

Ok

Step 27

Configure locales for all the languages that your system is going to be used with. Use UTF-8 locales wherever possible.

$ sudo dpkg-reconfigure locales

In this example, German and Japanese locales are generated in addition to the default locale for the system environment.

Configuring locales

Locales to be generated:

[*] de_DE.UTF-8 UTF-8
[*] en_US.UTF-8 UTF-8
[*] ja_JP.UTF-8 UTF-8

OK

Keep en_US.UTF-8 as the default locale for the system environment.

Configuring locales

Default locale for the system environment:

en_US.UTF-8

OK

Step 28

The Desktop was disabled in GNOME 3.28. This decision was not universally popular at the time. However, developers pointed to the fact that, as an unmaintained feature, it stood in the way of other improvements. The following command hides the now orphaned Desktop folder from view.

$ echo Desktop >> ~/.hidden

Step 29

Install additonal Debian packages to give you a functional GNOME desktop.

$ sudo apt-get install --show-progress --yes apostrophe aptitude cheese cups curl debian-reference deja-dup file-roller foliate foomatic-db-compressed-ppds gcolor3 gnome-clocks gnome-color-manager gnome-connections gnome-dictionary gnome-epub-thumbnailer gnome-firmware gnome-keysign gnome-maps gnome-mpv gnome-power-manager gnome-session-canberra gnome-shell-extension-bluetooth-quick-connect gnome-shell-extension-dashtodock gnome-shell-extension-no-annoyance gnome-shell-extension-tiling-assistant gnome-shell-extensions-extra gnome-software-plugin-flatpak gnome-software-plugin-snap gnome-sound-recorder gnome-tweaks gnome-video-effects-frei0r gpodder mpv-mpris nautilus-share neofetch network-manager-config-connectivity-debian network-manager-openconnect-gnome network-manager-openvpn-gnome network-manager-ssh-gnome network-manager-vpnc-gnome ooo-thumbnailer pdfarranger plymouth-themes printer-driver-cups-pdf playerctl rhythmbox-plugin-alternative-toolbar rhythmbox-plugin-cdrecorder rsync seahorse seahorse-daemon seahorse-nautilus shotwell smbclient soundconverter ssh-askpass-gnome synaptic transmission-gtk task-laptop ufw unattended-upgrades wireguard yubioath-desktop && sudo ufw enable

Step 30

Replace the text output during system boot with a graphical splash screen.

$ sudo sed -i 's/GRUB_CMDLINE_LINUX_DEFAULT="quiet"/GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"/' /etc/default/grub && sudo update-grub2

Step 31

Configure neofetch to display information about your system on the command-line.

$ echo -e '\n# use Neofetch to display information about the system\nif [ -f /usr/bin/neofetch ]; then\n clear && neofetch;\nfi' >> ~/.bashrc && source ~/.bashrc

Step 32

Enable the unattended installation of important upgrades.

$ sudo dpkg-reconfigure unattended-upgrades

Step 33

If in Step 5 you selected a wireless interface as the primary network interface for use during the installation, you will need to re-authenticate after rebooting.

Enable the Network Manager for the primary network interface and reboot your system.

$ sudo sed -i 's/managed=false/managed=true/' /etc/NetworkManager/NetworkManager.conf&&sudo sed -i '/# The primary network interface/,$d' /etc/network/interfaces&&sudo reboot

Step 34

Enable the installation of Flatpaks from Flathub.

$ sudo -- bash -c 'flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo'

Step 35

Install applications from Flathub.

$ sudo flatpak install --assumeyes flathub com.vixalien.sticky dev.geopjr.Collision dev.geopjr.Tuba io.gitlab.adhami3310.Converter org.cryptomator.Cryptomator org.gustavoperedo.FontDownloader org.libreoffice.LibreOffice org.keepassxc.KeePassXC

Step 36

Install applications from the Snap Store.

$ sudo snap install bitwarden chromium

Step 37

The snap directory in your home folder is not supposed to be accessed manually. Use the following command to hide it from view.

$ echo snap >> ~/.hidden

Step 38

By default, Debian installs the Extended Support Release (ESR) version of Firefox. The ESR receives crash fixes, security fixes and policy updates as needed.

The flatpak, on the other hand, installs the Rapid Release version of Firefox. In contrast to the ESR, the Rapid Release receives major updates at least every four weeks. Both versions can be used concurrently and are available on your desktop as Firefox ESR and Firefox Web Browser, respectively.

Install Firefox Rapid Release and set it as the default browser.

$ sudo flatpak install --assumeyes org.mozilla.firefox && xdg-settings set default-web-browser org.mozilla.firefox.desktop

Consider using different themes to easily distinguish between the two versions.

All done!

Step 39

Prevent yourself from accidentally breaking Debian by reading about some of the most commonly made mistakes.

Setting the compilation tag using eyeD3 and Linux

With the eyeD3 command you can easily set the compilation tag for compatibility of your MP3 files with Apple gear. Just change to the directory containing the files making up the compilation (or soundtrack) and execute the following command:

user@debian:/path/to/your/compilation/$ find ./ -name "*.mp3" -exec eyeD3 --set-text-frame=TCMP:1 '{}' ';' &

Hope this snippet proves useful.
github.com

Executing Linux commands in the background using screen

The screen command allows you to detach a running process from a session and then reattach it at a later time. Its use is simple:

user@debian:~$ screen yourlinuxcommand

Now that yourlinuxcommand is executing, press Ctrl+A followed by D to detach the screen.
Obtain a list of all the running screen processes:

user@debian:~$ screen -ls
There is a screen on:
       18470.pts-0.server(02/03/14 10:03:43)     (Detached)
1 Socket in /var/run/screen/S-user.

Note the screen id in the above output. Use the screen id to reattach the session at anytime:

user@debian:~$ $ screen -r 18470.pts-0.server

www.thegeekstuff.com, www.linuxjournal.com

The Debian Administrator’s Handbook

“We wanted the book to be freely available (that is under the terms of a license compatible with the Debian Free Software Guidelines of course). There was a condition though: a liberation fund had to be completed to ensure we had a decent compensation for the work that the book represents. This fund reached its target of €25K in April 2012.” Raphaël Hertzog and Roland Mas hope that you will enjoy the book.
debian-handbook.info

Redirecting mail for the local root user

postfix is Ubuntu’s default mail transfer agent (MTA) and can be configured to deliver mail using a relay host that requires SMTP authentication. Get the necessary packages with the following command:

user@ubuntu:~$ sudo apt-get install postfix bsd-mailx

Begin to configure your postfix installation by choosing satellite system as the general type of configuration. Enter the local machine name as the mail name (eg mycomputer.edafe.de) and the SMTP server address of your email service provider as the SMTP relay host (eg smtp.relayhost.com). Edit the file /etc/postfix/main.cf and add the following:

smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = noanonymous

Create the file /etc/postfix/sasl_passwd and make the following entries:

smtp.relayhost.com user:password

Substitute smtp.relayhost.com with the address of the SMTP relay host and user:password with your login details. Continue by executing the following three commands:

user@ubuntu:~$ sudo chown root.root /etc/postfix/sasl_passwd
user@ubuntu:~$ sudo chmod 600 /etc/postfix/sasl_passwd
user@ubuntu:~$ sudo postmap hash:/etc/postfix/sasl_passwd

Instruct postfix to reload its settings with the following command:

user@ubuntu:~$ sudo /etc/init.d/postfix reload

Making changes to the alias table

The aliases table provides a system-wide mechanism to redirect mail for local recipients. Edit the file /etc/aliases to contain the following entries:

postmaster: root
root: localuser
localuser: user@yourdomain.com

The localuser is the system administrator. Substitute user@yourdomain.com with the email address that you would like mail for the root user to be redirected to. Finally, update /etc/aliases.db using the following command:

user@ubuntu:~$ sudo newaliases

Mail for the local root user from now on will automatically be forwarded to user@yourdomain.com , using smtp.relayhost.com as the relay host.
www.postfix.org, help.ubuntu.com

Monitoring hard disks with smartmontools

SMART stands for Self-Monitoring, Analysis and Reporting Technology and is built into most modern hard disks. The smartd daemon is part of smartmontools and monitors a disk’s SMART data for any signs of hardware problems. SMART is available with Parallel and Serial ATA disks, drives appearing as either /dev/hd* or /dev/sd*, respectively. Use the following command to obtain relevant information for your system:

user@ubuntu:~$ df -hl

If required, start by configuring postfix to redirect mail for the local root user. Get the necessary packages with the following command:

user@ubuntu:~$ sudo apt-get install smartmontools bsd-mailx

Configuring smartd

Edit the file /etc/smartd.conf and comment out any lines beginning with DEVICESCAN. If you are using a netbook or a laptop, add the following line for the smartd daemon to monitor the device /dev/sda:

/dev/sda -a -d ata -n standby -o on -S on -m root -M daily -M test

If you are using a desktop or a server, add the following line for the smartd daemon to monitor the device /dev/hda:

/dev/hda -a -d ata -n never -o on -S on -s (L/../../7/04|S/../.././02) -m root -M daily -M test

See man smartd.conf for more information on how to tailor the operation of smartd to your needs.

Starting smartd

Edit the file /etc/default/smartmontools and uncomment the line containing start_smartd=yes. Restart the smartd daemon with the following command:

user@ubuntu:~$ sudo /etc/init.d/smartmontools restart

Verify that the local root user has received a test message from the smartd daemon. From now on, the smartd daemon will monitor the disk and, in the event of impending disk failure, alert the local root user by email.

Still sending naked email?

“In a world of repressive governments and a growing reliance on insecure networks, there’s no way anyone can be sure their most sensitive messages aren’t intercepted by the forces of darkness. But you can make it mathematically improbable that all but the most well-funded snoops could ever make heads or tales of your communications.” Use Dan Goodin’s step-by-step guide to email encryption and keep your communications private.
www.theregister.com