Bash Script to Send Email Notification Easily

Use the mail command in Bash like this: echo "Message body" | mail -s "Subject" [e-mail] to send an email notification.

Examples

Inputecho "Hello!" | mail -s "Test Email" [e-mail]

OutputSends an email with subject 'Test Email' and body 'Hello!' to [e-mail]

Inputecho "Backup completed" | mail -s "Backup Status" [e-mail]

OutputSends an email with subject 'Backup Status' and body 'Backup completed' to [e-mail]

Inputecho "Disk space low" | mail -s "Alert" root@localhost

OutputSends an alert email with subject 'Alert' and body 'Disk space low' to root@localhost

How to Think About It

To send an email from a Bash script, you need to create the message content and use a command that can send emails, like mail. You provide the message body via standard input and specify the subject and recipient as command options.

Algorithm

1

Create the message body as a string or from a command output

2

Use the <code>mail</code> command with the <code>-s</code> option to set the email subject

3

Pipe the message body into the <code>mail</code> command

4

Specify the recipient email address

5

Run the script to send the email notification

Code

bash

#!/bin/bash

message="Hello, this is a notification from your script."
subject="Notification"
recipient="[e-mail]"

echo "$message" | mail -s "$subject" "$recipient"
echo "Email sent to $recipient"

Output

Email sent to [e-mail]

Dry Run

Let's trace sending a notification email with message 'Hello, this is a notification from your script.'

1

Set variables

message='Hello, this is a notification from your script.' subject='Notification' recipient='[e-mail]'

2

Send email

echo "$message" | mail -s "$subject" "$recipient"

3

Print confirmation

echo 'Email sent to [e-mail]'

Step	Action	Value
1	Set message	Hello, this is a notification from your script.
1	Set subject	Notification
1	Set recipient	[e-mail]
2	Send email command	echo "$message" | mail -s "$subject" "$recipient"
3	Print output	Email sent to [e-mail]

Why This Works

Step 1: Prepare message and details

The script stores the email message, subject, and recipient in variables for easy reuse and clarity.

Step 2: Send email using mail command

The mail command sends the email; the message is piped into it, and the subject and recipient are specified with options.

Step 3: Confirm email sent

A simple echo statement confirms the script ran and attempted to send the email.

Alternative Approaches

Using sendmail command

bash

#!/bin/bash

recipient="[e-mail]"
subject="Notification"
message="Hello from sendmail!"

sendmail $recipient <<EOF
Subject: $subject

$message
EOF
echo "Email sent using sendmail to $recipient"

sendmail is more complex but powerful; requires correct headers and formatting.

Using mailx command

bash

#!/bin/bash

message="Hello from mailx!"
subject="Notification"
recipient="[e-mail]"

echo "$message" | mailx -s "$subject" "$recipient"
echo "Email sent using mailx to $recipient"

mailx is similar to mail but may have more features depending on system.

Complexity: O(1) time, O(1) space

Time Complexity

Sending an email is a single operation with no loops, so it runs in constant time.

Space Complexity

The script uses a fixed amount of memory for variables and pipes, so space is constant.

Which Approach is Fastest?

All methods run in constant time; differences depend on system mail setup, not script complexity.

Approach	Time	Space	Best For
mail command	O(1)	O(1)	Simple email notifications
sendmail command	O(1)	O(1)	Advanced email formatting
mailx command	O(1)	O(1)	Enhanced mail features