How to send/receive local emails in Linux Mint/VirtualBox

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This post was originally published on my personal blog mariadcampbell.com.

I have begun acquainting myself with cron jobs in Linux, and I want to be
able to send myself local emails inside Linux Mint/VirtualBox if the
cron job was successful or not. It is actually quite easy, but not so easy
to find all the correct information! But I finally did!

At first I thought that I should send an email from Linux Mint Terminal to my
actual Gmail email. I installed postfix and then mailutils because I was
trying out the mail command and needed to install mailutils if I wanted to
use it.

After some investigation, I found it to be too complicated and not even
necessary. There is a simple built-in Linux (Mint)
mail user agent program called mailx. According to
Geeks for Geeks,

The mailxutility is an enhanced version of the mail command. Along with
the functionality provided by the original mail command, it provides extra
features like the ability to send attachments by using the -a (-A actually)
flag. The mailx command is available from a variety of different packages:
bsd-mailx, heirloom-mailx, and mailutils.

I ended up using the mail command, but mailx is used in the same way. They
are both available with the mailutils package, which is what I installed in
order to be able to use the mail command. What is interesting is that mail and
mailx are two separate commands, and they have their own bin. But according to
Geeks for Geeks,

Even though the mailx command is a newer version of the original mail utility,
it can still be referenced with the ‘mail’ keyword.

In other words, they can be interchangeable. When I did try to send an email
to my Gmail account, of course it did not work. I don't think I could
accomplish that these days from a local email address inside my
Linux Mint/VirtualBox instance. So that's why I decided to stick with this
approach since I am working inside of a virtual machine anyway. It will be
interesting to find out if I can send an email to Gmail in macOS when I set up
cron jobs there. That's for another time!

I used the following command to send myself a local email with the mail
(and/or mailx) command from Terminal:

echo "My first test message" | mail -s "My first test message subject line" maria@maria-VirtualBox
# or
echo "My first test message" | mailx -s "My first test message subject line" maria@maria-VirtualBox

And then to view my local mail/mailx inbox, I run the following in
Terminal:

mail
# or
mailx

And when I hit the Enter key, the following is output to Terminal:

"/var/mail/maria": 1 message 1 unread
>U 1 Maria            Thu Jul 25 16:53  17/601  My first test message sub...
?

And if I want to delete the message, I type the following after the ?
prompt:

? d 1

And then hit the Enter key followed by Control key + D key, which
exits me out of the shell. But before I actually exit out, the
following is output:

Held 0 messages in /var/mail/maria

The -s flag stands for subject. There are other options to choose from with
mailx. In order to learn more, check out man mailx in Terminal.

It is also possible to send emails to other users on the system. For
example, I could send an email to user magdala. Then I could take
advantage of things like attaching a file to the email. Let's say I run
the following in Terminal:

cat /home/maria/Desktop/history.txt | mail -s "Hi Magdala, just checking in!" magdala@maria-VirtualBox

Since I am sending the email via Terminal, and it is being received by
user magdala also via Terminal, I have to stick to what the CLI
(Command Line Interface or Terminal) understands. So for the Terminal
(bash specifically) to interpret the contents of my history.txt file
properly, I use the cat command which then becomes the stdout of the
mailx command, thereby redirecting the stdin
cat /home/maria/Desktop/history.txt of mailx as stdout of mailx to
magdala@maria-VirtualBox.

If I wanted to send a copy of the email to myself I could do the
following:

cat /home/maria/Desktop/history.txt | mail -s "Hi Magdala, just checking in!" magdala@maria-VirtualBox maria@maria-VirtualBox

And if the user magdala wants to save the contents to a file, she can
copy it from the email body and paste it into a new .txt file. It is
not perfect on the receiving end, but for cron job notification purposes,
for example, it would work just fine. As well as .txt files containing
log information, for example, that are not too lengthy.

If I did not do it as above using the cat command, the contents of the file
would be unintelligible.

Related Resources

• mailx in Linux: Geeks for Geeks

• How to send attachments using mailx command: LinuxQuestiona.org

• The Cron daemon in Linux and how to create a cron job:
  mariadcampbell.com