Very simple. Just type the following command to add a new user with a default home directory:

$ useradd -m username

To change the password of the new user, type:

$ passwd username


For some reasons I can't explain, I had to make some little modifications in the source code of the downloaded libraries. Here are the steps I followed:

  • Following the recommendations at:, I executed the following commands:
    • git clone git://
    • qmake


      make install
  • When I typed the "make" command, some errors appeared (I need to clarify that I entirely installed QT creator and other packets from Debian official repositories (apt-get). The first issue was that I did not have installed packages qtbase5-private-dev and libqt5websockets5-dev (maybe I needed to install qtdeclarative5-dev).
  • This solved the dependencies issues, but compilation errors like this remained: qmqtttopicfilter.cpp:206:26: error: no match for ‘operator==’ (operand types are ‘QString’ and ‘QLatin1Char’)
                 || d->filter == QLatin1Char('#')
  • Following the same recommendations, I opened the file with my QT and made the following modifications at the qmqtttopicfilter.cpp file:
    • || d->filter == QLatin1Char('#')             -------------------->                  || d->filter[0] == QLatin1Char('#')
    • if (level != QLatin1Char('+') && level !=   -------------------------->        if (level[0] != QLatin1Char('+') && level !=
  • Voilà.. the problem is fixed and now it can be compiled. Then I tested the result with the subscriptions example.




Type: grep -rnw '/path/to/somewhere/' -e 'pattern'
  • (Examples with eth0)
  • Examples of network configuration files.
    • In /etc/network/interfaces
      • With DHCP

                               #The primary network interface
                               allow-hotplug eth0
                               iface eth0 inet dhcp

      • With static IP

                               iface eth0 inet static
                               address <IP ADDRESS>
                               netmask <SUBNET MASK>
                               network <NETWORK ADDRESS>
                               broadcast <BROADCAST ADDRESS>
                               gateway <GATEWAY ADDRESS>

  • DNS servers. In /etc/resolv.conf
  • Adding default address to local route table. Enter: sudo route add default gw <GATEWAY ADDRESS>
  • Restart eth0
    • ifdown eth0
    • ifup eth0

Embedding fonts in a PDF file (useful for compatibility with IEEE). Command: ps2pdf -dCompatibilityLevel=1.4 -dPDFSETTINGS=/prepress <IN>.ps <OUT>.pdf