 <p>Read carefully <a href="http://man7.org/linux/man-pages/man2/mknod.2.html" rel="nofollow">mknod(2)</a> man page (e.g. type <code>man 2 mknod</code> in a terminal).</p> <blockquote> <pre><code> The mode argument specifies both the permissions to use and the type of node to be created. It should be a combination (using bitwise OR) of one of the file types listed below and the permissions for the new node. </code></pre> </blockquote> <p>BTW, you might -and probably should- use <a href="http://man7.org/linux/man-pages/man3/mkfifo.3.html" rel="nofollow">mkfifo(3)</a> instead (or, in a shell script or terminal, the <a href="http://man7.org/linux/man-pages/man1/mkfifo.1.html" rel="nofollow">mkfifo(1)</a> command).</p> <p>The permissions are mostly useful for processes which are <a href="http://man7.org/linux/man-pages/man2/open.2.html" rel="nofollow">open(2)</a>-ing an already existing named pipe.</p> <p><sup>With appropriate permission settings, you could restrict the usage of a FIFO to e.g. only the members of some given group.</sup></p> <p>Read also <a href="http://advancedlinuxprogramming.com/" rel="nofollow">Advanced Linux Programming</a>, <a href="http://man7.org/linux/man-pages/man7/fifo.7.html" rel="nofollow">fifo(7)</a>, <a href="http://man7.org/linux/man-pages/man7/credentials.7.html" rel="nofollow">credentials(7)</a>, <a href="http://man7.org/linux/man-pages/man7/capabilities.7.html" rel="nofollow">capabiities(7)</a>, and about <a href="http://en.wikipedia.org/wiki/Setuid" rel="nofollow">setuid</a>.</p>