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Port 80 requires elevated privileges

When running on Ubuntu 16.04 with a user other than root, you are not allowed to publish node.js apps on port 80 by default. This can be fixed though:

sudo apt-get install libcap2-bin
sudo setcap cap_net_bind_service=+ep `readlink -f \`which node\``

Kill a running process

First, you need to find the id of that process.

For example, if Blender is hogging the memory, find its id with

ps -A | grep blender

The first number is the id. Kill it with

kill -9 the-blender-id-you-found

Remove a PPA

To remove the Midori PPA, run:

sudo add-apt-repository --remove ppa:midori/ppa

Install Google Chrome on Ubuntu 16.04

wget https://dl.google.com/linux/direct/google-chrome-stable_current_amd64.deb
sudo dpkg -i --force-depends google-chrome-stable_current_amd64.deb
sudo apt-get install -f

Install Google Chrome

Source: Tutorial on installing Google Chrome

Run the following commands:

wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | sudo apt-key add -
sudo sh -c 'echo "deb http://dl.google.com/linux/chrome/deb/ stable main" >> /etc/apt/sources.list.d/google.list'
sudo apt-get update
sudo apt-get install google-chrome-stable

Backup and restore an Ubuntu server


Install Joomla on Ubuntu

sudo vi /etc/apache2/sites-enabled/000-default

Add entries:

<VirtualHost *:80>
  DocumentRoot /home/useraccount/www/domainname.loc
  ServerName domainname.loc

Locally, edit the etc/hosts file to point to the server:

sudo vi /etc/hosts

Restart Apache

sudo /etc/init.d/apache2 restart

On a local machine, to see the website before it's public, add an entry, where is the IP of the server and domainname.loc is the domain name: domainname.loc

Finally, browse


Useful commands

Append a user to an existing group without removing his current groups

sudo usermod -aG <groupname> <username>


Prevent cats switching off Ubuntu by walking on the power button

Comment out with a # in front of "/sbin/shutdown -h now" in /etc/acpi/powerbtn.sh

Install LAMP stack on Ubuntu

Reference document

sudo apt-get update
sudo apt-get install tasksel
sudo tasksel install lamp-server

Setup SSL on Ubuntu

Start from your home directory.

Create your server's public and private keys and set pass phrase

sudo openssl genrsa -des3 -out server.key 1024

You will be asked a passphrase. Make sure you don't forget it.

Create certificate request file

sudo openssl req -new -key server.key -out server.csr
  1. Re-use the same passphrase defined in the previous step, then enter:
  2. country name, ex: NL for Netherlands
  3. state of province name, ex: Noord-Holland
  4. name of your city, ex: Amsterdam
  5. organisation name, ex: eBabel
  6. business unit, ex: Web Development
  7. your own name, ex: Nadjib Amar
  8. your e-mail address, ex: hello@ebabel.eu
  9. a challenge password (not the same thing as your passphrase)
  10. optional company name. I use my main domain name: ebabel.eu

Create self signed certificate

sudo openssl x509 -req -days 365 -in server.csr -signkey server.key -out server.crt

You will be prompted to enter your passphrase again.

Update httpd.conf

sudo vi /etc/apache2/httpd.conf

In httpd.conf, insert text below then save with :wq

Servername localhost

Restart Apache:

sudo service apache2 restart

Copy the server.crt and server.key files into the appropriate directory

cd /etc/apache2
sudo mkdir ssl
sudo cp ~/server.key /etc/apache2/ssl/
sudo cp ~/server.crt /etc/apache2/ssl/

Enable the Apache SSL module

sudo a2enmod ssl

Restart Apache

sudo /etc/init.d/apache2 restart

Stub SSL conf. file and symlink (Symbolic Link)

sudo ln -s /etc/apache2/sites-available/default-ssl /etc/apache2/sites-enabled/000-default-ssl

Edit the Default-SSL configuration file

There are too many changes to make by simply using vi, so I'll make a copy of default-ssl, download it, edit it in Gedit then upload it to the server.

sudo cp /etc/apache2/sites-available/default-ssl ~/

Download the default-ssl file with sftp and edit it. Insert the following configuration lines in bold between the IfModule and VirtualHost tags:

<IfModule mod_ssl.c>

NameVirtualHost *:443
SSLStrictSNIVHostCheck off

<VirtualHost *:443>

Duplicate the big block of settings for each VirtualHost that needs SSL

<VirtualHost *:443>
DocumentRoot /var/www/nl.sitedomain.www/
ServerName www.sitedomain.nl

[...more code, left unchanged...]


<VirtualHost *:443>
DocumentRoot /var/www/nl.anothersitedomain.www/
ServerName www.anothersitedomain.nl

[...more code, left unchanged...]


Upload the default-ssl file and overwrite the one that was originally there.

Restart Apache

sudo /etc/init.d/apache2 restart

Setup self signed SSL certificate for NodeJS on Windows

Create the keys:

openssl genrsa -des3 -out privatekey.key 1024
openssl req -new -key privatekey.key -out csrkey.csr
openssl x509 -req -days 365 -in csrkey.csr -signkey privatekey.key -out certificate.crt

Convert to Windows format:

openssl x509 -in certificate.crt -out certificate.pem -outform PEM
cat certificate.crt privatekey.key > privatekey.pem

Setup self signed SSL certificate for NodeJS on Mac OS X

sudo ssh-keygen -f host.key
sudo openssl req -new -key host.key -out request.csr
sudo openssl x509 -req -days 365 -in request.csr -signkey host.key -out server.crt
sudo openssl rsa -in host.key -out host.nopass.key