Apt sources.list for Ubuntu 16.04 LTS on ARM64

Here is my sources list:

deb http://ports.ubuntu.com/ubuntu-ports/ xenial main restricted
deb-src http://ports.ubuntu.com/ubuntu-ports/ xenial main restricted
deb http://ports.ubuntu.com/ubuntu-ports/ xenial-security main restricted
deb http://ports.ubuntu.com/ubuntu-ports/ xenial-updates main
deb-src http://ports.ubuntu.com/ubuntu-ports/ xenial-updates main restricted

Can't connect to mail server

Connections to my postfix+imap server are "blocked" (connection refused).
Turns out the portreserve system is broken... it blocks ports the mail server needs!

for daemon in portreserve clamd cyrus-imapd spamassassin amavisd postgrey postfix
do
/sbin/service $daemon stop
done
for daemon in postfix postgrey amavisd spamassassin cyrus-imapd clamd portreserve
do
/sbin/service $daemon start
done

Upgrade Drupal by using a patch file

From drupal.org Last updated August 27, 2012. Created on January 15, 2009. Edited by fuerst, lukas.fischer, adellefrank, rezboom.

The standard procedure to upgrade Drupal to the latest release is to download it from drupal.org and follow the included UPGRADE.txt. For administrators using the UNIX shell, it may be easier by using a patch file instead. To follow the procedure described below you need the diff and patch commands which are available at most LINUX distributions.

Update #7203

The following updates returned messages
media_wysiwyg module
Update #7203

CKEditor integration has been moved to the Media CKEditor module.If you are using the stand-alone CKEditor module in combination with the CKEditor plugin provided by Media WYSIWYG then you must download and enable the Media CKEditor module.

Install OctoPrint on BeagleBone (white)

#add a user (I choose pi)
sudo useradd -m -c "Pi Octoprint" pi
#Be sure to give him a password
sudo password pi
#make sure it's up to date
sudo apt-get update
#install python building tools
sudo apt-get install build-essential python-dev python-pip python-virtualenv

NOW you can start with the instructions https://github.com/foosel/OctoPrint
Specifically,

Workload Scheduler users: You need rlwrap

If you use the Linux shell very much, you find its history functions very useful. You can recall previous commands very easily, just using the arrow keys.
If you use the Workload Scheduler command-line interfaces, conman and composer, you really miss the history. Sure there's the redo command, but its editing capability is limited to the last command you typed.

Backup and restore mySQL (MariaDB) database

Backup:
/usr/bin/mysqldump --user=dbuser --password=dbpass --host=localhost --add-drop-table dbname > backups/mydbdump.sql

Restore:
(if the db exist)
# mysql -u root -p[root_password] [database_name] < dumpfilename.sql

mysql -u root -ps3cre3t

mysql> create database dbname;
Query OK, 1 row affected (0.02 sec)

# mysql -u root -ps3cre3t db < /tmp/mydbdump.sql