Posted on
• Administration

How to Send Email Notifications from Bash Scripts

Author
  • User
    Linux Bash
    Posts by this author
    Posts by this author

Sending email notifications from a Bash script can be useful for alerts, reports, or task completion updates. Here's how to achieve this on a Linux system:

1. Prerequisites

Ensure you have an email client or mail transfer agent (MTA) installed. Common options include: - mail or mailx: Simplest email clients. - sendmail: Powerful MTA for advanced configurations. - ssmtp or msmtp: Lightweight MTAs, often used with Gmail or other SMTP services. - mutt: Versatile email client for sending attachments.

2. Using mail or mailx

Step 1: Install mailx

Install the package (if not already installed):

sudo apt install mailutils     # For Debian/Ubuntu
sudo yum install mailx         # For CentOS/RHEL

Step 2: Send an Email

Basic command:

echo "Email body text" | mail -s "Subject Here" recipient@example.com

Step 3: Use in a Bash Script

Example:

#!/bin/bash

# Variables
EMAIL="recipient@example.com"
SUBJECT="Backup Status"
BODY="The backup job completed successfully at $(date)."

# Send email
echo "$BODY" | mail -s "$SUBJECT" $EMAIL

3. Sending Attachments with mail

To send a file as an attachment:

echo "Email body text" | mail -s "Subject Here" -A /path/to/file recipient@example.com

4. Using sendmail

Step 1: Install sendmail

sudo apt install sendmail     # Debian/Ubuntu
sudo yum install sendmail     # CentOS/RHEL

Step 2: Send an Email

Example:

#!/bin/bash

# Email details
FROM="your_email@example.com"
TO="recipient@example.com"
SUBJECT="Task Status"
BODY="The scheduled task completed successfully."

# Build the email
{
  echo "From: $FROM"
  echo "To: $TO"
  echo "Subject: $SUBJECT"
  echo
  echo "$BODY"
} | sendmail -t

5. Using ssmtp or msmtp

These tools are ideal for sending emails via SMTP (e.g., Gmail).

Step 1: Install ssmtp or msmtp

sudo apt install ssmtp       # For lightweight SMTP
sudo apt install msmtp        # Alternative lightweight SMTP

Step 2: Configure SMTP

Edit the configuration file (/etc/ssmtp/ssmtp.conf or /etc/msmtprc) and include your SMTP server details:

# Example for Gmail
root=your_email@gmail.com
mailhub=smtp.gmail.com:587
AuthUser=your_email@gmail.com
AuthPass=your_password
UseSTARTTLS=YES

Step 3: Send Email

echo "Email body text" | ssmtp recipient@example.com

6. Using mutt for Advanced Features

Step 1: Install mutt

sudo apt install mutt

Step 2: Send an Email with an Attachment

echo "Email body text" | mutt -s "Subject Here" -a /path/to/attachment -- recipient@example.com

7. Using Gmail API or External Libraries (Advanced)

For secure and scalable email notifications, you can use Python scripts or APIs like the Gmail API. This is useful when integrating with larger applications.

8. Debugging Email Issues

  • Check Logs: Email errors are often logged in /var/log/mail.log or /var/log/maillog.
  • Test SMTP Server: bash telnet smtp.example.com 25
  • Verify Installation: Ensure the necessary packages (mail, sendmail, etc.) are correctly installed and configured.

9. Practical Example: Email Notifications for a Cron Job

Here's how to notify on job completion:

#!/bin/bash

# Task
tar -czf /backup/documents.tar.gz /home/user/documents

# Check if the command succeeded
if [ $? -eq 0 ]; then
    echo "Backup completed successfully" | mail -s "Backup Success" admin@example.com
else
    echo "Backup failed" | mail -s "Backup Failure" admin@example.com
fi

This guide provides multiple methods for sending email notifications from Bash scripts.

Related posts