Linux mail Command Usage with Examples

You can send email from a Linux server with the mail command, directly or from shell scripts.

How it works

When you send a message, mail calls the system sendmail program (/usr/sbin/sendmail). That program hands the message to the local Mail Transfer Agent (MTA), which delivers it over SMTP.

If you see an error such as send-mail: Cannot open mail:25, no MTA like Postfix is running on the server.

Install the mail command

The command comes from one of these packages:

1. mailutils (GNU mailutils)
2. heirloom-mailx / s-nail
3. bsd-mailx

Their options differ a little. Install it:

CentOS, AlmaLinux and Red Hat:

sudo yum install mailx -y

Debian and Ubuntu:

sudo apt install mailutils

You also need an MTA such as Postfix to send mail.

Send a mail

mail -s 'Enter the subject' user@example.com

-s sets the subject. Type your message, then press Ctrl+D on an empty line to send. The screen shows EOT.

Send the message from a file

mail -s 'The Subject' user@example.com < /root/testemail.txt

Send with a pipe

echo 'THIS IS A TEST EMAIL' | mail -s 'Enter the subject' user@example.com

Several recipients

echo 'THIS IS A TEST EMAIL' | mail -s 'Enter the subject' user1@example.com,user2@example.com

CC and BCC

echo 'THIS IS A TEST EMAIL' | mail -s 'Enter the subject' -c cc1@example.com,cc2@example.com user@example.com

For a blind copy use -b.

Set the From name and address

With mailx:

echo 'THIS IS A TEST EMAIL' | mail -s 'Enter the subject' -r 'Tom <tom@example.com>' user@example.com

With GNU mailutils use -a "From: Tom <tom@example.com>".

Set a Reply-To address

echo 'THIS IS A TEST EMAIL' | mail -s 'Enter the subject' -S replyto=reply@example.com user@example.com

Attach a file

mailx:

echo 'See the attachment' | mail -s 'Report' -a /root/report.pdf user@example.com

GNU mailutils uses -A for attachments.

Use it in a script

#!/bin/bash
df -h | mail -s "Disk report for $(hostname)" admin@example.com

Add it to cron to send a report every day.

Quick recap

• Install mailx or mailutils, and a working MTA like Postfix.
• echo "text" | mail -s "Subject" user@example.com is the fastest way.