How to send mail with sendmail command line

The classic sendmail command!

To send an email using the sendmail command line, you'll need to follow these steps:

Step 1: Prepare your email

Create a text file containing the email message you want to send. The file should have the following format:

To: [email protected]
From: [email protected]
Subject: Your email subject

Your email body

Replace [email protected], [email protected], and Your email subject with the actual values.

Step 2: Use the sendmail command

Open a terminal or command prompt and navigate to the directory where your email file is located. Then, use the following command:

sendmail [email protected] < your_email.txt

Replace [email protected] with the email address of the recipient, and your_email.txt with the name of your email file.

Options and flags

You can customize the sendmail command by adding options and flags. Here are some common ones:

-t or --input-file: Specify the input file containing the email message. (Default is -)
-f or --from: Set the sender's email address.
-s or --subject: Set the email subject.
-a or --attach: Attach a file to the email.
-v or --verbose: Enable verbose mode, which shows more detailed output.

For example:

sendmail -t -f [email protected] -s "Your email subject" [email protected] < your_email.txt

Tips and variations

If you want to send an email with a specific SMTP server, you can use the -S or --smtp-server option followed by the server's hostname or IP address. For example:
```
sendmail -t -S smtp.example.com -f [email protected] -s "Your email subject" [email protected] < your_email.txt
```

To send an email with a specific port number, use the -P or --port option followed by the port number. For example:

sendmail -t -S smtp.example.com -P 587 -f [email protected] -s "Your email subject" [email protected] < your_email.txt

If you want to send an email with a specific authentication mechanism (e.g., username and password), you can use the -u or --username and -p or --password options. For example:
```
sendmail -t -S smtp.example.com -P 587 -u your_username -p your_password -f [email protected] -s "Your email subject" [email protected] < your_email.txt
```
Remember to replace the placeholders with your actual values and adjust the options and flags according to your needs.