user19014: In the Arduino IDE on my RPi on the top there is a header that says, File, Edit, Tools and help. 
Following a Magpi article it said to go to tools then serial port and change that depending on what board you use. The only problem is that it's not there, when I click tools I scroll down and there grayed out it says, serial port. 
Why is this grayed out? And why can I not change it? Also, what port should be used for an Uno?

user4143: It's greyed out because it can't find any serial ports.
That could be because:

There aren't any detected (not got the right kernel modules loaded)
You don't have permission to access the serial ports (are you in the dialout group?)

Have you followed the Linux installation instructions? http://playground.arduino.cc/Linux/All

19014: <p>In the Arduino IDE on my RPi on the top there is a header that says, File, Edit, Tools and help. </p>

<p>Following a Magpi article it said to go to tools then serial port and change that depending on what board you use. The only problem is that it's not there, when I click tools I scroll down and there <strong>grayed out</strong> it says, serial port. </p>

<p>Why is this grayed out? And why can I not change it? Also, what port should be used for an Uno?</p>
 4143: <p>It's greyed out because it can't find any serial ports.</p>

<p>That could be because:</p>

<ul>
<li>There aren't any detected (not got the right kernel modules loaded)</li>
<li>You don't have permission to access the serial ports (are you in the <code>dialout</code> group?)</li>
</ul>

<p>Have you followed the Linux installation instructions? <a href="http://playground.arduino.cc/Linux/All" rel="nofollow">http://playground.arduino.cc/Linux/All</a></p>
