The mail command can be used to send an email. Use apt-get or yum to install the mail command.

~]# yum install mailx

In this example, an email is sent to john.doe@example.com. This assumes there is a user account for john.doe on the example.com email server. In this example, after typing "Hello John", press Ctrl + D to send the email.

[root@server1 ~]# mail john.doe@example.com
Subject: Example subject
Hello John
EOT

Subject

The -s option can be used to include the subject in the command line, so that you are not prompted for the subject.

[root@server1 ~]# mail -s "Example subject" john.doe@example.com

Message Body

Echo can be used to add a message in the command line, so that you are not prompted for the message.

[root@server1 ~]# echo "Example message" | mail john.doe@example.com

Carbon copy

The -c option can be used to carbon copy.

[root@server1 ~]# mail -c jane.doe@example.com john.doe@example.com

The -b option can be used to blind carbon copy.

[root@server1 ~]# mail -b jane.doe@example.com john.doe@example.com

Verbose

The -v (verbose) option can be used to diplay more information.

[root@server1 ~]# mail -v john.doe@example.com
250-mail.example.com
250-PIPELINING
250-SIZE 10240000
250-VRFY
250-ETRN
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN
Hello user1
EOT

Mail log

View the mailog to ensure the email was delivered.

[root@server1 ~]# tail /var/log/maillog
. . . 
Mar 27 21:23:16 mail1 postfix/local[2079]: 94D795845: to=<user1@localhost>, orig_to=<user1@localhost>, relay=local, delay=0.05, delays=0.03/0.01/0/0, dsn=2.0.0, status=sent (delivered to Maildir)
. . .