Compare two files and print only the unmatched values UNIX
<p>I have two files suppose 1st.dat</p>

<pre><code>a
b
c
d
</code></pre>

<p>and another file sppose 2nd.dat</p>

<pre><code>d
e
f
g
</code></pre>

<p>my output should be like </p>

<pre><code>a
b
c
e
f
g
</code></pre>

<p>I have tried using diff and sdiff but I am not getting the output as I mentioned. Please Help</p>