Find the Real Path of a Symbolic Link in Linux

I was searching for the install location of the java installation on my Raspberry Pi and came across the java bin file in my /usr/bin directory.  However, the bin file showed up as a symbolic link (shown in cyan) and I needed to find the source.


Google to the rescue!  You can simply use the preinstalled pacakge, readlink.

$ readlink /usr/bin/java

Fing Network Tools – An Android App for Discovering IP Addresses of Devices on your Network

On Google+, I recently came across a post entitled Top Ten Android Apps for use with Raspberry Pi which mentioned Fing – Network Tools by Overlook that allows you to discover the IP and MAC addresses of devices on your network.  This is a very handy app that I’m definitely adding to my list.

Image courtesy of Overlook

Hide an NFC Tag Underneath a Coaster

Recently I purchased a set of  Kamor® NFC tags to tinker around with.  NFC tags are passive devices that an Android phone can read as unique identifier and trigger specific events. Edit: For a further explanation on the applications of NFC tabs, please see MKBHD’s video below.  The problem with the tags, however, is that they have to be out in the open to easily use them.  Sitting on my couch the other day, I was looking at my THIRSTYSTONE coaster sitting on my end table and had a brilliant idea; embed the NFC tag in the coaster.  The coasters that we have happen to have a cork bottom that is a little thicker than the NFC tag and so I was able to cut out a piece of the cork and stick the NFC tag inside.  Also, before attempting this modification, I made sure that my Moto X was able to sense the tag through the coaster.




Tools needed: Utility knife, coaster, and NFC tag.


Tracing the NFC tag on the cork bottom of the coaster.


The outline of the NFC tag.


The bottom side of the coaster after cutting out the cork.


The final modification after sticking the tag to the coaster.


Reformat a Raspberry Pi SD Card Using Diskpart in Windows 7

In can be tricky reformatting a Raspberry Pi SD card in Windows 7 due to the multiple partitions that Raspian creates.  Here’s a simple way using the built in Diskpart in Windows 7.

Insert the SD card into an SD card reader and open a Windows command prompt console and start Diskpart.


List all of your disks.

DISKPART> list disk

Select your SD card disk.

DISKPART> select disk <#>

List all of your disks to ensure that the correct disk is selected – the selected disk will have an asterisk next to it.

DISKPART> list disk

Clean the disk.


Create a primary partition.

DISKPART> create partition primary

Create and format the primary filesystem.

DISKPART> format fs=fat32 quick

Assign the disk to a Windowsdrive letter so it shows up in Windows Explorer.

DISKPART> assign

Your disk is now ready for use.


Updating the System Time on a Raspberry Pi

The Raspberry Pi for some reason does not properly update the system time automatically.  To do this, simply install ntpdate.

View your current date and time:

$ date

Install ntpdate:

$ sudo apt-get install ntpdate

To update the time zone, simply remove the current local time file and make a new symbolic link to your timezone file:

$ sudo rm /etc/localtime
$ ls /usr/share/zoneinfo
$ ls /usr/share/zoneinfo/America
$ sudo ln -s /usr/share/zoneinfo/America/Los_Angeles /etc/localtime

Restart the ntp service:

$ sudo service ntp restart

Check the date again:

$ date

Your Raspberry Pi time should now be set!