How can I find the missing integers in a unique and sequential list (one per line) in a unix terminal?
<p>Suppose I have a file as follows (a sorted, unique list of integers, one per line):</p>

<pre><code>1
3
4
5
8
9
10
</code></pre>

<p>I would like the following output (i.e. the missing integers in the list):</p>

<pre><code>2
6
7
</code></pre>

<p>How can I accomplish this within a bash terminal (using awk or a similar solution, preferably a one-liner)?</p>