Listing Running Services on Linux with systemctl

Listing active services is essential for system monitoring and troubleshooting. Whether you’re investigating a hung process, checking if a daemon started correctly, or auditing what’s actually running on your system, knowing how to query service status quickly saves time.

Basic Command

The standard way to list running services across all modern Linux distributions is:

systemctl list-units --type=service --state=running

This shows only services that are currently active. The output includes the service name, load state, active state, and a brief description.

Common Variations

To see all services (including stopped ones):

systemctl list-units --type=service --all

For a more compact output with just service names:

systemctl list-units --type=service --state=running --no-pager

The --no-pager flag is useful in scripts or when piping output to other commands.

To see services that failed to start:

systemctl list-units --type=service --state=failed

Detailed Service Information

If you need to inspect a specific service in detail:

systemctl status nginx

This shows the full status, recent log entries, and whether the service is enabled to start at boot.

To see all enabled services (those that start automatically):

systemctl list-unit-files --type=service --state=enabled

Real-Time Resource Monitoring

For a top-like view of service resource consumption by cgroup:

systemd-cgtop

This tool displays CPU usage, memory consumption, and I/O metrics for each service in real time. It’s invaluable when tracking down resource-hungry daemons without spawning multiple monitoring tools.

Filtering and Searching

Pipe systemctl output to grep for targeted searches:

systemctl list-units --type=service --all | grep mysql

Or use systemctl’s built-in filtering:

systemctl list-units --type=service --state=running --no-pager | grep -E "nginx|apache|mysql"

Legacy Commands

The older service --status-all command still works on most distributions for backward compatibility:

service --status-all

However, this lacks the dependency tracking and detailed state information that systemctl provides. Avoid relying on it for new scripts or automation.

Practical Use Cases

Check if a service is running before attempting to restart it:

systemctl is-active nginx && echo "Running" || echo "Not running"

Get a count of total running services:

systemctl list-units --type=service --state=running --no-pager | wc -l

Export a list of all enabled services for documentation:

systemctl list-unit-files --type=service --state=enabled --no-pager > enabled-services.txt

Modern systemd provides far more insight into service state, dependencies, and resource usage than older init systems. Mastering systemctl is essential for effective Linux system administration.

Troubleshooting Common Issues

When encountering problems on Linux systems, follow a systematic approach. Check system logs first using journalctl for systemd-based distributions. Verify service status with systemctl before attempting restarts. For network issues, use ip addr and ss -tulpn to diagnose connectivity problems.

Package management issues often stem from stale caches. Run dnf clean all on Fedora or apt clean on Ubuntu before retrying failed installations. If a package has unmet dependencies, try resolving them with dnf autoremove or apt autoremove.

Related System Commands

These commands are frequently used alongside the tools discussed in this article:

• systemctl status service-name – Check if a service is running
• journalctl -u service-name -f – Follow service logs in real time
• rpm -qi package-name – Query installed package information
• dnf history – View package transaction history
• top or htop – Monitor system resource usage

Quick Verification

After applying the changes described above, verify that everything works as expected. Run the relevant commands to confirm the new configuration is active. Check system logs for any errors or warnings that might indicate problems. If something does not work as expected, review the steps carefully and consult the official documentation for your specific version.