====== Ubuntu Tips, Tricks and Notes ======

===== Mirrors =====
The default mirror is **%%http://us.archive.ubuntu.com/ubuntu/%%**

The preferred mirror is **%%http://mirrors.mit.edu/ubuntu/%%**

==== Determine the fastest mirror ====
  snap install mirrorselect
  mirrorselect --country us
  
===== Post-Installation =====
Make the output of the **df** command more friendly and less cluttered by creating a system-wide alias for it:
  echo "alias df='df -h -x squashfs -x tmpfs -x devtmpfs'" >> /etc/profile.d/aliases.sh
  
Make sure to set the "always_set_home" variable in the sudoers file (using **visudo**)

==== Disable IPv6 ====
To disable IPv6 on Ubuntu during boot time, open the /etc/default/grub file using your favorite text editor with root privileges and change/add:
  FROM:
  GRUB_CMDLINE_LINUX_DEFAULT=""
  GRUB_CMDLINE_LINUX=""
  TO:
  GRUB_CMDLINE_LINUX_DEFAULT="ipv6.disable=1"
  GRUB_CMDLINE_LINUX="ipv6.disable=1"
Once you have made the above change within the /etc/default/grub file execute the following command to apply the GRUB changes:
  sudo update-grub
  
Reboot the system afterwards.

==== Enable console screen blanking ====
Edit the /etc/default/grub file using your favorite text editor with root privileges and add the string **consoleblank=600** to the GRUB_CMDLINE_LINUX_DEFAULT and GRUB_CMDLINE_LINUX lines for a 10-minute timeout.  

Once you have made the above change within the /etc/default/grub file execute the following command to apply the GRUB changes:
  sudo update-grub

Reboot the system afterwards.

==== To install Samba: ====

  sudo apt-get install samba cifs-utils

==== To install NFS: ====

  sudo apt-get install nfs-common nfs-kernel-server

==== To install mysql: ====

  sudo apt install mysql-server
  sudo mysql_secure_installation

==== Customizing the MOTD ====
Put any customization data into /etc/motd

==== Installing apache and php ====
  sudo apt update
  sudo apt install apache2
  sudo apt install php libapache2-mod-php
  sudo apt install php-mysql php-gd php-xml
  sudo apt install phpmyadmin php-mbstring php-gettext

==== Install phpmyadmin ====

  sudo apt update
  sudo apt install phpmyadmin php-mbstring php-zip php-gd php-json php-curl
  sudo phpenmod mbstring
  sudo systemctl restart apache2
  mysql
  mysql> SELECT user,authentication_string,plugin,host FROM mysql.user;
  mysql> ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY '<password>';

==== Installing Portainer to manage Docker containers ====

  sudo docker run -d -p 9443:9443 -p 8000:8000 --name portainer --restart=always -v /var/run/docker.sock:/var/run/docker.sock -v portainer_data:/data portainer/portainer-ce:latest

==== Disable interactive restart prompt while upgrading packages with apt ====
The trouble in this case is with the ''needrestart'' command, which is part of the apt-get upgrade process in Ubuntu now. By default this is set to “interactive” mode which causes the interruption of scripts.

To change this behavior, we can edit the ''/etc/needrestart/needrestart.conf'' file, changing the line:

''#$nrconf{restart} = 'i';''

to

''$nrconf{restart} = 'a';'' (if we want to restart the services automatically) or ''$nrconf{restart} = 'l';'' to simply list the services that need restart.

===== Ubuntu Desktop (Gnome/GUI) Stuff =====

==== Set login screen default resolution ====
  - Login and set the screen resolution as desired.
  - Once set, copy the file **~/.config/monitors.xml** to **/var/lib/gdm3/.config/monitors.xml**.
  - Ensure the user/group ownership is set to **gdm.gdm**.
  - Reboot the system to apply the changes.

==== Eliminating the annoying repeated authentication dialogs when logging in via xrdp ====
Edit the file **/etc/polkit-1/localauthority/50-local.d/45-allow-colord.pkla**; paste the following config into it and then save it:

  [Allow Colord all Users]
  Identity=unix-user:*
  Action=org.freedesktop.color-manager.create-device;org.freedesktop.color-manager.create-profile;org.freedesktop.color-manager.delete-device;org.freedesktop.color-manager.delete-profile;org.freedesktop.color-manager.modify-device;org.freedesktop.color-manager.modify-profile
  ResultAny=no
  ResultInactive=no
  ResultActive=yes

If the issue persists afterwards, a reboot of the system should resolve it.

==== Fixing the Low Battery Alert ====
Found on Reddit; will "clean it up" later...

cd /etc/UPower\\
sudo nano UPower.conf\\
If you set UsePercentageForPolicy=true then edit the percentage lines to your liking, such as:\\
PercentageLow=50\\
PercentageCritical=35\\
If you prefer a time based approach, then set UsePercentageForPolicy to false and set the time notification options to your liking, such as:\\
TimeLow=1200\\
TimeCritical=300\\
Hit ctrl+X to save the UPower.conf file and close out of nano editor.\\
Reboot computer or sudo systemctl restart upower for changes to take effect.\\