How to Install, Automate, and Use ClamAV Antivirus on Ubuntu 

Step 2: Update the Virus Signatures Database

Before scanning, update the virus database to detect the latest threats.

Stop the background update service temporarily:

Manually trigger the database update:

3. Restart the background updater daemon:

2. Scanning Downloaded Files Manually

To verify that a freshly downloaded file is safe before opening it, you can run a targeted scan on your Downloads folder or individual files.

Scan a Single File:

Scan the Entire Downloads Folder:

To scan all files in your Downloads directory and show only infected files in the output, use the -r (recursive) and --infected flags:

3. Setting Up an Automated Weekly System Scan via Terminal Script

You can set up a simple Bash script and schedule it with cron so your system runs a regular weekly virus scan in the background.

Step 1: Create the Scan Script

Open the terminal and create a new script file:

Paste the following script into the editor:

Make the script executable:

Step 2: Schedule the Weekly Cron Job

Open the root crontab configuration:

Add the following line at the bottom to run the scan every Sunday at 02:00 AM:

4. What to Do If a Virus or Threat Is Found

If ClamAV flags a file as infected, do not open or execute it. Here are the steps to isolate or remove it safely:

Option 1: Quarantine the Infected File

Moving the file to a quarantine directory prevents accidental execution while allowing you to inspect it:

Option 2: Automatically Delete Infected Files

If you are confident that the infected file is malicious and not a critical system file, you can tell ClamAV to remove it upon detection: