Sendmail unix utility

Sendmail is a popular open-source mail transfer agent (MTA) that is used to send and receive emails on Unix-like operating systems. It is a command-line utility that allows users to send emails from the command line.

Here are some basic sendmail commands:

Sending an email

• sendmail -t < email_file>: Send an email from the command line. The -t option tells sendmail to read the email from a file. The file should contain the email message in the format of a standard email.
• sendmail -v [email protected] "Subject: This is a test email": Send an email to a specific recipient with a subject line.

Options

• -v: Verbose mode. Sendmail will print more information about the email sending process.
• -t: Read the email from a file.
• -f: Specify the sender's email address.
• -s: Specify the subject line of the email.
• -a: Specify the recipient's email address.

Example email file

Here is an example of an email file that can be used with the sendmail command:

From: [email protected]
To: [email protected]
Subject: This is a test email

This is a test email sent from the command line using sendmail.

Common sendmail commands

• sendmail -v: Send an email with verbose mode enabled.
• sendmail -t email_file: Send an email from a file.
• sendmail -f [email protected] [email protected]: Send an email from a specific sender to a specific recipient.
• sendmail -s "Subject: This is a test email" [email protected]: Send an email with a specific subject line.

Security considerations

• Sendmail is a powerful tool that can be used to send spam or malicious emails. Be careful when using sendmail and make sure to follow best practices for email security.
• Sendmail can be configured to use authentication and encryption to secure email transmission.

Alternatives to sendmail

• Postfix: A popular alternative to sendmail that is also an MTA.
• Exim: Another popular alternative to sendmail that is also an MTA.
• Mailx: A simpler alternative to sendmail that is also a command-line email client.