Linux commands send mail

9 mail/mailx command examples to send emails from command line on Linux

Send mails from command line

The mail command is an essential one that should be available on any linux server so that various services and other web applications can generate and transmit emails.

In a previous post on mail command we saw how the mail command can be used to send emails from the command line on your linux server.

In this tutorial we shall be using an enhanced version of the mail command. Its called mailx (or just mail when installed), and it can do many more things than what the older mail command from gnu mailutils package can do.

How does it work

The mail/mailx command needs a local smtp server (MTA) running in order to deliver the emails. THe route taken by the email is somewhat like this —

The recipient MTA would be gmail’s smtp server if your recipient is someone at gmail.com for instance. For the local MTA, you need to install an smtp server like Postfix. A basic installation of Postfix with minimal configuration would work in most cases.

Install the mailx command

On Ubuntu/Debian based systems the mailx command is available from 2 different packages —

We shall be using the heirloom-mailx package because it has more features and options.
On CentOS/Fedora based systems, there is only one package named «mailx» which is the heirloom package.

To find out what mailx package is installed on your system, check the «man mailx» output and scroll down to the end and you should see some useful information.

Using the mailx command

Once installed, the mailx command can be directly referenced with the name mail, so you just type in that in the command line.

1. Simple mail

Run the following command, and then mailx would wait for you to enter the message of the email. You can hit enter for new lines. When done typing the message, press Ctrl+D and mailx would display EOT.

After than mailx automatically delivers the email to the destination.

2. Take message from a file

The message body of the email can be taken from a file as well.

The message can also be piped using the echo command —

3. Multiple recipients

To send the mail to multiple recipients, specify all the emails separated by a comma

4. CC and BCC

The «-c» and «-b» options can be used to add CC and BCC addresses respectively.

5. Specify From name and address

To specify a «FROM» name and address, use the «-r» option. The name should be followed by the address wrapped in «<>«.

6. Specify «Reply-To» address

The reply to address is set with the internal option variable «replyto» using the «-S» option.

7. Attachments

Attachments can be added with the «-a» option.

8. Use external SMTP server

This is an exclusive feature, that you get only with heirloom mailx and not bsd mailx, or the mail command from gnu mailutils or the mutt command.

The mailx command can use an external smtp server to use to relay the message forward. The syntax is a bit lengthy but makes sense.

Here is a breakdown

You can use the gmail smtp servers and send emails via your gmail account. That is so cool!
For gmail specifically you would need to enable less secure apps settings before you can send mail like that.

9. Verbose — watch smtp communication

When using external smtp servers, you can choose to watch the entire smtp communication that is done in the background. This is useful specially when testing or debugging smtp servers.

Troubleshooting

In case the mails are not being delivered properly you need to check a few things. The first thing to check is that an smtp server (mta) is running locally. The netstat command can tell that

If an stmp server like Postfix is running and still mails are not going, then try re-configuring Postfix for example. On Ubuntu/Debian systems, this can be done with the dpkg-reconfigure command

Then retry, the mail command and it should work. If it still doesn’t, try contacting your server provider.

No mails from local systems

If you try to send mails from your local computer to a gmail address, your mail would most likely be rejected, so don’t try doing that.

This is because ordinary computers connected to internet address have an ip address that is not associated with any valid domain as such, and gmail strictly verifies such credentials before approving any mail to go through.

Notes and Resources

Apart from mailx, there are other tools like Swaks and smtp-cli that can be used to send mails from command line and support various features like specifying smtp servers and adding attachments and so on.

However the mailx command is available in the default repositories of most common distros, so can be installed easily. Further it maintains a syntax very similar to that of the mail command which makes it a drop in replacement for the older mail command.

The mailx command is even capable of reading mails from remote IMAP servers, but that is something we kept out of this post and would talk later. To learn more check the man page for the mailx command with «man mailx».

A Tech Enthusiast, Blogger, Linux Fan and a Software Developer. Writes about Computer hardware, Linux and Open Source software and coding in Python, Php and Javascript. He can be reached at [email protected] .

14 thoughts on “ 9 mail/mailx command examples to send emails from command line on Linux ”

might be worth pointing out that most of this won’t work on a lot of systems,
illegal option — S
illegal option — a
illegal option — r

You don’t detail how mailx determines the smtp envelope from address
>>> MAIL FROM:
Obviously it’s [email protected], but how can this be over-ridden with mailx ?

Hello.
I want my printer to send emails to external email addresses like Gmail.com, I setup the ubuntu server as explained and set the ubuntu server as the smtp server on printer. I can send emails from ubuntu server to gmail, but it’s not relaying emails to gmail.com from the printer itself. What should I do? Please help.

I would like to know, whether we have option to send the attachment with password protected through mailx UNIX command? can anyone help me on this.

I have a cron job like this:
tar -czf /home/backup/myfolder/myfile_$(/bin/date +\%Y\%m\%d).tgz /home/public_html -X /home/backup/myfile-exclude.txt

I have edit my cron job to this:
tar -czf /home/backup/myfolder/myfile_$(/bin/date +\%Y\%m\%d).tgz /home/public_html -X /home/backup/myfile-exclude.txt | mail -s “Cron Daemon: mywebsite.com – files backup” [email protected]

Normally the Cron job puts some info into the Body, but how do I get this to work? I have tried with:

I am using attachment command in phone script but it is not working whether if the same command runing on emulator

You could setup home computer as well but it needs to integrate with the from address mail domain SMTP relays to send emails.

I have followd your “tuto” ( use Centos7 )

I still have this error ?? can you help me ?

Connecting to 82.216.111.2:25 . . . connected.

220 smtp3.tech.numericable.fr ESMTP Postfix
>>> EHLO centos7
250-smtp3.tech.numericable.fr
250-PIPELINING
250-SIZE 10240000
250-ETRN
250-ENHANCEDSTATUSCODES
250 8BITMIME
>>> AUTH LOGIN
503 5.5.1 Error: authentication not enabled
smtp-server: 503 5.5.1 Error: authentication not enabled

my mailrc file ;
#set smtp-use-starttls
set nss-config-dir=

/.mozilla/firefox/yyyyyyyy.default/
set ssl-verify=ignore
set smtpd_sasl_auth_enable
# set smtp
set smtp=smtp://smtp.numericable.fr:25
set [email protected]
# tell mailx that it needs to authorise
set smtp-auth=login
# set the user for SMTP
# set [email protected]
set [email protected]
# set the password for authorisation
set smtp-auth-password=xxxxxx
bye.

Hi,
I am not able to use FROM option using -r, specified in 5th point.

Good info. Just to clarify, sendmail/postfix/etc are MTAs and either relay through an smtp relay or directly communicates to the destination smtp servers, depending on how the MTA is configured. So the flow would be mail_client > mta > smtp_relay OR destination_smtp_server > recipient’s inbox. So using common programs as an example: mailx > postfix > smtp.yourorg.com > smtp.gmail.com > [email protected] inbox. A common example where this configuration is used is Linux servers that need to send to external email recipients (alerts and stuff). In that case, you configure the Linux server to use your outgoing smtp server via sendmail or postfix or other MTA to relay the email by allowing the IP of the Linux server to relay through the smtp server.

Thank you for your post. Can I use Mailx for send up to 15000 mails ? I’m searching a alternative to online newsletter service (payment)!

I hope your ISP blocks you.

Yes, you can use Mailx or any other scripts to send any volume of emails provided that your domain SMTP relay is capable to handle volume. Do you run your own mail server or using one of the shared hosting? If you run yours … yes you could send any volume but may take few hours to send. You can’t send out emails just using home computer as those will not be delivered to end users or will directly go in users Spam folder. If you need to use home computer … you would need to hop / forward your emails to your domain SMTP relay of “from user” to send the emails to users. Reach-out if you need professional help for setting up mail server to handle your newsletter … you would need one dedicated public IPAddress on a Linux server. I am assuming that these are registered users for business and you are authorized to send them newsletter.

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Send mail from command line with external smtp server on Linux

Send mail via SMTP servers

The default mail command on the Linux terminal, uses the local smtp server (mta) on port 25 to send emails. However at times you need to specify an external smtp server to use for sending mails.

For example you have just setup an smtp server, like Postfix or Exim, then you would want to test it out to check if it is receiving and relaying emails properly or not.

Being able to send mails from command line using this external smtp server is quick rather than having to setup a mail client like Thunderbird on your local machine.

There are 2 command line utilites called mailx and swaks that can be used to send mails using external smtp server. These are quite useful when you need to send emails from a bash script in an automated manner.

1. mailx command

The mailx command is available from many different packages like mailutils, heirloom-mailx etc. First you need to use the aptitude command to search the mailx package available for your system. Here is an example

To find out which mailx command your system is using, run the readlink command. Here is a sample output.

Not all mailx variants can use external smtp servers to send mail. Only the one that comes from the s-nail package (pulled by heirloom-mailx) can do it.

We shall be using heirloom-mailx since it allows to specify smtp connection details in a single command and issue and email quickly.

Now send an email with an external smtp server like this —

Here is a step by step version of the same command —

Make sure to use the correct settings, like port number, authentication mechanism etc. The command would produce verbose output giving full details of the smtp communication that goes on behind, making it very easy to test and debug.

Note: The package heirloom-mailx was removed from Ubuntu version 18 onwards. Now you have to install the s-nail package.

The s-nail command is the same as heirloom mailx command. Just the name is different. Run the same command above by replacing mailx with s-nail and it should work.

If you are using the latest version of s-nail (14.9.x) the syntax for specifying the smtp server details might be slightly different. Check the latest manual here

2. Swaks command

Swaks (Swiss army knife for SMTP) is a simple command line tool that can be used to test smtp servers to check if they are doing they job properly. It supports TLS as well.

Install swaks on Ubuntu/Debian with the following command

Now send the email

All the options are pretty self explanatory. The «—server» option specifies the external SMTP server to use, «—auth» specifies the type of authentication. The «-tls» option tells swaks to use STARTTLS.

Check the man page for more options.

A Tech Enthusiast, Blogger, Linux Fan and a Software Developer. Writes about Computer hardware, Linux and Open Source software and coding in Python, Php and Javascript. He can be reached at [email protected] .

5 thoughts on “ Send mail from command line with external smtp server on Linux ”

telnet your.smtp.server 25
HELO your.ip
MAIL FROM:
RCPT TO:
DATA
Subject: YOUR SUBJECT
Your message then end with a point
.
(then disconnect)

I use Thunderbird as a mail client and have been experimenting with sending mail through Thunderbird via the bash command line. I want to be able to send an email within a bash script.

I can successfully make Thunderbird open a compose window to send a mail, but I really want it to happen in the background with NO human interaction. Is there an option I can give Thunderbird on the command line to send the message straight away ?

This is what I’ve got so far :-

thunderbird -compose “preselectid=id3,[email protected],subject=’Dropbox Sync Log `date +%D`’,body=’`cat

I fully realise I don’t need to attach a file as well as catting it into the message. I’ve just left it in to show that attachments are possible from the command line, that’s all.

If someone knows how to make Thunderbird actually send the email from the command line instead of opening a window in Thunderbird client, I’d be delighted to hear from you.

Thanks a lot. very useful.

–body is required for swaks in order to read message body from standard input; otherwise the default body of “This is a test mailing” will be used.

[QUOTE from man]
–body [body-specification]
Specify the body of the email. The default is “This is a test
mailing”. If no argument to –body is given, prompt to supply one
interactively. If ‘-‘ is supplied, the body will be read from
standard input. If any other text is provided and the text
represents an open-able file, the content of that file is used as
the body. If it does not represent an open-able file, the text
itself is used as the body.

If the message is forced to MIME format (see –attach) the argument
to this option will be included unencoded as the first MIME part.
Its content-type will always be text/plain.

Hi, great examples to connect to a smtp server from command line. I also like this: https://github.com/gasparfm/gscripts/blob/master/gemail.sh It uses sendmail (you can have nullmailer configured to connect to a smtp server). The best of it is that you can send attachments.

I use it to send by emails files generated directly on a server.

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