How to Easily Configure WiFi in Raspberry Pi

Any version of Raspberry Pi can be very easily configured with WiFi access. Coupled with ssh or vnc, it allows you to manage your Pi remotely. Here is the simplest way I could think of, illustrated by a screenshot and detailed below.

Once your Raspberry Pi boots up, you will get to this shiny screen. Now open a Terminal by clicking on the black square icon on top-left of the screen.Screenshot from 2017-01-04 11-29-18

This opens a Terminal where you type in:

sudo leafpad /etc/network/interfaces

This opens up a notepad-like editor. Make three changes to the text as shown in the highlighted section:

  1. Change manual to dhcp in the line starting with “iface wlan0”
  2. Replace wifi_id with the Wireless Access ID / SSID
  3. Replace password with your actual password for Wireless Access

Now save it (Ctrl-S) like notepad and exit it. The terminal should still remain open.

Now either reboot the Pi or restart the network with the following command on Terminal (don’t forget to press <Enter> after you typed):

sudo service networking restart

Wait for a few minutes for the WiFi to come up. On latest Raspbian with PIXEL, you can verify by seeing the two blue arrows in opposite direction, as can be seen from the screenshot.

Safest way to Update and Upgrade Raspbian Wheezy (Raspberry Pi OS)

There are plethora of instructions on the web to update and upgrade Raspbian and they work too, under normal conditions. However as Raspberry Pi is increasingly being used for Mission Critical tasks, it is important to adopt a procedure which won’t leave you with broken packages or worst, a un-bootable Operating System with your data on it. The following is a simple procedure, with explanations which will make sure that your Pi remains working.

First let’s update and upgrade the Pi with a single line command, run from terminal:

sudo apt-get update -y && sudo apt-get upgrade -y && echo success

This will update and upgrade your Pi and if successful will print success at the end.

Now reboot the Pi with:

sudo reboot

Normally Pi would reboot properly 99% of the time. If it refuses to boot then you can select the old kernel while booting to get back an usable version of Raspbian OS.

After this only two more steps remain. First is to dist-upgrade the Raspbian OS:

sudo apt-get dist-upgrade -y && sudo apt-get autoremove -y && echo success

You  may wonder why I didn’t do it the very first time. While dist-upgrade is better than plain upgrade as it can intelligently install packages based on dependency, upgrade retains the older kernel and gives you a way to back out safely, unlike dist-upgrade. The procedure outlined above protects your OS from cases where the upgrade is broken for any reason.

Now all that is left is to reboot again to make sure everything is OK.:

sudo reboot

You may notice that I didn’t ask you to rpi-update, an instruction you will find at many places online. This is because you do not need rpi-update, the necessary firmware updates are already installed when you upgraded Raspbian. In fact, and I speak from experience, rpi-update can break your running system. Let’s leave that bleeding edge to who really needs it. If you are reading this article, then it can safely be said you don’t.

I used sudo apt-get autoremove to remove any extra packages.

The && before echo success makes sure success is printed only when the previous command succeeds.

Disk space is premium in SD Card. So it may not be out of place to check for available disk space before running update, upgrade or dist-upgrade:

df -h

To save some space clean up the downloaded debian archives with:

sudo apt-get clean

Now you understand why automating Raspbian updates / upgrades is a bad idea, unless you want to use the Raspberry pi only for testing purposes.

Advanced Note on why rpi-update was not suggested:

It’s current Raspberry Pi practice not to use this [ rpi-update ] unless you REALLY need it as it can bring in a non-working kernel (i.e. the latest bleeding edge version, which is not guaranteed to work).

My thoughts are that it is not actually required once you have done the apt-get update/upgrade cycle.

James, Raspberry Pi Foundation (Trading)

How to remove Squeak and Scratch from Raspberry Pi: Raspbian Jessie and Wheezy Distro

Raspbian Jessie and Wheezy distribution includes Squeak and Scratch. While these can be helpful educational tools for students which provides a gentle introduction to programming, it doesn’t have much use for others. The following instructions will remove both Squeak and Scratch from your Raspberry Pi (Raspbian distribution). It saves 92.7 MB and 1.15 MB respectively in Jessie and another 10.2 MB with subsequent autoremove, so over 100 MB space saved.

root@puma:/home/pi# apt-get remove --purge scratch*
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Note, selecting 'nuscratch' for regex 'scratch*'
Note, selecting 'squeak-plugins-scratch-dbg' for regex 'scratch*'
Note, selecting 'squeak-plugins-scratch' for regex 'scratch*'
Note, selecting 'python3-pifacedigital-scratch-handler' for regex 'scratch*'
Note, selecting 'libdirectory-scratch-perl' for regex 'scratch*'
Note, selecting 'libdirectory-scratch-structured-perl' for regex 'scratch*'
Note, selecting 'scratch' for regex 'scratch*'
Package 'libdirectory-scratch-perl' is not installed, so not removed
Package 'libdirectory-scratch-structured-perl' is not installed, so not removed
Package 'squeak-plugins-scratch-dbg' is not installed, so not removed
The following packages were automatically installed and are no longer required:
  fonts-roboto gtk2-engines-clearlookspix liblightdm-gobject-1-0
  libxfce4ui-1-0 libxfce4util-bin libxfce4util-common libxfce4util6
  libxfconf-0-2 lightdm-gtk-greeter pimixer pipanel squeak-vm wiringpi
  xfce-keyboard-shortcuts xfconf
Use 'apt-get autoremove' to remove them.
The following packages will be REMOVED:
  nuscratch* python3-pifacedigital-scratch-handler* scratch*
  squeak-plugins-scratch*
0 upgraded, 0 newly installed, 4 to remove and 1 not upgraded.
After this operation, 92.7 MB disk space will be freed.
Do you want to continue? [Y/n] y
(Reading database ... 136309 files and directories currently installed.)
Removing nuscratch (20160115) ...
Removing 'diversion of /usr/bin/scratch to /usr/bin/scratch.old by nuscratch'
Removing 'diversion of /usr/bin/squeak to /usr/bin/squeak.old by nuscratch'
Removing 'diversion of /usr/share/scratch/locale/ja_HIRA.po to /usr/share/scratch/locale/ja_HIRA.po.old by nuscratch'
Removing 'diversion of /usr/share/scratch/locale/ja.po to /usr/share/scratch/locale/ja.po.old by nuscratch'
Purging configuration files for nuscratch (20160115) ...
Removing python3-pifacedigital-scratch-handler (2.0.5-1) ...
Purging configuration files for python3-pifacedigital-scratch-handler (2.0.5-1) ...
Removing scratch (1.4.0.6~dfsg1-5) ...
Purging configuration files for scratch (1.4.0.6~dfsg1-5) ...
Removing squeak-plugins-scratch (1.4.0.2~svn.r83-2) ...
Processing triggers for hicolor-icon-theme (0.13-1) ...
Processing triggers for man-db (2.7.0.2-5) ...
Processing triggers for gnome-menus (3.13.3-6) ...
Processing triggers for desktop-file-utils (0.22-1) ...
Processing triggers for mime-support (3.58) ...
Processing triggers for shared-mime-info (1.3-1) ...
root@puma:/home/pi# apt-get remove --purge squeak*
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Note, selecting 'squeak-plugins-scratch-dbg' for regex 'squeak*'
Note, selecting 'squeak-vm' for regex 'squeak*'Mathematica
Note, selecting 'squeak-plugins-scratch' for regex 'squeak*'
Package 'squeak-plugins-scratch' is not installed, so not removed
Package 'squeak-plugins-scratch-dbg' is not iAfter this operation, 1,151 kB disk space will be freed.nstalled, so not removed
The following packages were automatically installed and are no longer required:And 
  fonts-roboto gtk2-engines-clearlookspix liblightdm-gobject-1-0
  libxfce4ui-1-0 libxfce4util-bin libxfce4util-common libxfce4util6
  libxfconf-0-2 lightdm-gtk-greeter pimixer pipanel wiringpi
  xfce-keyboard-shortcuts xfconf
Use 'apt-get autoremove' to remove them.
The following packages will be REMOVED:
  squeak-vm*
0 upgraded, 0 newly installed, 1 to remove and 1 not upgraded.
After this operation, 1,151 kB disk space will be freed.
Do you want to continue? [Y/n] y
(Reading database ... 135057 files and directories currently installed.)
Removing squeak-vm (1:4.10.2.2614-1.1+b1) ...
Processing triggers for shared-mime-info (1.3-1) ...
Processing triggers for gnome-menus (3.13.3-6) ...
Processing triggers for desktop-file-utils (0.22-1) ...
Processing triggers for mime-support (3.58) ...
Processing triggers for gnome-icon-theme (3.12.0-1) ...
Processing triggers for man-db (2.7.0.2-5) ...

Don’t forget to run clean and autoremove:

apt-get clean

How to remove Wolfram Language and Mathematica from Raspberry Pi: Raspbian Jessie and Wheezy distro

Raspbian Jessie and Wheezy distribution includes Wolfram Language and Mathematica. While this can be helpful for students, it doesn’t have much use for others. The following instructions will remove both Wolfram and Mathematica from your Raspberry Pi (Raspbian distribution). It saves 658MB in Jessie.

sudo apt-get remove wolfram-engine
Reading package lists... Done
Building dependency tree 
Reading state information... Done
The following packages will be REMOVED:
 wolfram-engine
0 upgraded, 0 newly installed, 1 to remove and 59 not upgraded.
After this operation, 658 MB disk space will be freed.
Do you want to continue? [Y/n] y
(Reading database ... 150191 files and directories currently installed.)
Removing wolfram-engine (10.3.1+2016012407) ...
Processing triggers for man-db (2.7.0.2-5) ...
Processing triggers for gnome-menus (3.13.3-6) ...
Processing triggers for desktop-file-utils (0.22-1) ...
Processing triggers for mime-support (3.58) ...
Processing triggers for shared-mime-info (1.3-1) ...
Processing triggers for hicolor-icon-theme (0.13-1) ...

Then there is one final step:

sudo rm /usr/share/raspi-ui-overrides/applications/wolfram-language.desktop /usr/share/raspi-ui-overrides/applications/wolfram-mathematica.desktop

And you are done!

PS. You can read more about these free (not for commercial use) packages here.

Single line command to install PHP5, MySQL, Apache2, XCache, PHP-Pear on Raspberry Pi

Installing LAMP on Raspberry Pi is very very simple. It takes a single line to execute on terminal / console. Continue reading “Single line command to install PHP5, MySQL, Apache2, XCache, PHP-Pear on Raspberry Pi”