### Check Installed Packages (Debian/RedHat)

Source: https://endoflife.date/api/v1/products/graylog

Use these commands to check if Elasticsearch, Graylog, or MongoDB are installed on Debian-based or RedHat-based systems.

```bash
# Debian based
dpkg -l | grep -E ".(elasticsearch|graylog|mongo)."

# RedHat based
dnf list installed | grep -E ".*(elasticsearch|graylog|mongo).* "
```