Add Cron Output Section

Many of us have been bit by cron's silent failures, only to find out that our jobs haven't
been running for hours, or worse, days. Cron's output, though great in theory, isn't as
reliable or as helpful as it could be. Our team has made sure to include this common
"pitfall" in our teaching sessions and thought it would serve nicely here as well. Feedback
appreciated!

cron_101.rst

@@ -239,6 +239,17 @@ the top of a crontab file that affect all of the commands run by those crontabs.
 For example, you could modify the ``PATH``, ``MAILTO``, ``HOME``, or any other
 variable.
 
+Cron Output
+--------
+Output from cron commands can be emailed to the owner of the process using a local SMTP server, like ssmtp or postfix. 
+If you'd like the output to be sent to an email different than your ``root@yourhost`` address use the ``MAILTO="your@email"`` expression before the cron command. 
+An email will be sent containing the output from STDOUT/STDERR every time the command executes. 
+Unfortunately, the email gives no indication of the return status of the process (success or failure) and often leads to a cluttered inbox. 
+
+.. note:: If your crontab is misconfigured you won't receive an email at all. 
+Finding such failures (the lack of an email in your inbox) is hard to detect. 
+To save time and avoid these *silent failures*, it is better to use a service that will notify you only on cron failures. [#]_
+
 --------
 
 Footnotes
@@ -251,3 +262,5 @@ Footnotes
 .. [#] `English to crontab <http://corntab.com/>`_
 
 .. [#] `Where can I set environment variables that crontab will use? <http://stackoverflow.com/questions/2229825/where-can-i-set-environment-variables-that-crontab-will-use/10657111#10657111>`_
+
+.. [#] `Receive notifications when cron commands fail <https://deadmanssnitch.com/>`_