# How to List the Services in Linux Listing services in Linux is a common task for anyone managing or using a Linux system. Whether you want to check which services are running, enabled, or stopped, knowing how to list them helps you understand your system better. In this article, I’ll guide you through the most popular and reliable methods to list services on Linux. You’ll see commands that work on different Linux distributions and learn how to interpret their output. By the end, you’ll feel confident managing services and troubleshooting your Linux system with ease. ## Understanding Linux Services Linux services are background processes that perform specific tasks, like running a web server or managing network connections. These services are often called daemons. They start automatically when your system boots or can be started manually. Services are managed by different init systems depending on your Linux distribution. The two most common are: - **Systemd**: Used by most modern Linux distros like Ubuntu, Fedora, and Debian. - **SysVinit**: Older system still used in some distributions. Knowing which init system your Linux uses helps you choose the right commands to list services. ## Listing Services with systemd Most Linux systems today use systemd to manage services. It provides a powerful tool called `systemctl` to control and list services. ### Basic Commands to List Services To list all services on your system, open a terminal and type: ```bash systemctl list-units --type=service ``` This command shows all loaded service units, their status, and whether they are active or inactive. If you want to see all services, including those not currently loaded, use: ```bash systemctl list-unit-files --type=service ``` This lists all service files and their enablement status (enabled, disabled, static). ### Filtering Services by Status You can filter services by their state: - To see only active (running) services: ```bash systemctl list-units --type=service --state=running ``` - To see failed services: ```bash systemctl --failed ``` ### Understanding the Output The output columns include: - **UNIT**: The service name. - **LOAD**: Whether the service file is loaded. - **ACTIVE**: The high-level state (active, inactive). - **SUB**: More detailed state (running, exited). - **DESCRIPTION**: A short description of the service. ### Examples of Common Services You might see services like: - `ssh.service` – Secure Shell server. - `cron.service` – Job scheduler. - `network.service` or `NetworkManager.service` – Network management. ## Listing Services with SysVinit If your Linux system uses the older SysVinit system, you’ll use different commands. ### Using `service` Command To list all services, run: ```bash service --status-all ``` This command shows a list of services with symbols indicating their status: - `[ + ]` means the service is running. - `[ - ]` means the service is stopped. - `[ ? ]` means the status is unknown. ### Using `chkconfig` (Red Hat-based Systems) On some Red Hat-based systems, you can use: ```bash chkconfig --list ``` This lists services and their runlevel settings, showing which services start automatically. ### Using `/etc/init.d/` You can also check the `/etc/init.d/` directory, which contains scripts for services. Listing the files here shows available services: ```bash ls /etc/init.d/ ``` ## Using `ps` and `top` to See Running Services Sometimes, you want to see which services or daemons are currently running as processes. - Use `ps` to list processes: ```bash ps aux | grep -i service-name ``` - Use `top` or `htop` for a real-time view of running processes. This method shows active services but doesn’t provide enablement status. ## Checking Service Status with GUI Tools If you prefer graphical interfaces, many Linux desktop environments offer tools to manage services. - **GNOME System Monitor**: Shows running processes. - **KDE System Settings**: Has a module for managing services. - **Third-party tools**: Applications like `systemd-manager` provide GUI for systemd services. These tools are user-friendly for beginners but may not show all service details. ## Tips for Managing Services Knowing how to list services is just the start. Here are some tips to manage them effectively: - Use `systemctl start service-name` to start a service. - Use `systemctl stop service-name` to stop a service. - Use `systemctl enable service-name` to start a service at boot. - Use `systemctl disable service-name` to prevent a service from starting automatically. Always check the service status after changes with: ```bash systemctl status service-name ``` ## Summary Table of Commands | Init System | Command to List Services | Notes | |-------------|---------------------------------------------|----------------------------------------| | systemd | `systemctl list-units --type=service` | Lists active and inactive services | | systemd | `systemctl list-unit-files --type=service` | Lists all service files and enablement | | SysVinit | `service --status-all` | Lists services with status symbols | | SysVinit | `chkconfig --list` | Shows services and runlevels (Red Hat)| | SysVinit | `ls /etc/init.d/` | Lists service scripts | ## Conclusion Listing services in Linux is a straightforward task once you know which commands to use. Whether your system uses systemd or SysVinit, you have reliable tools to see which services are running, enabled, or stopped. This knowledge helps you maintain your system’s health and troubleshoot issues quickly. I encourage you to try these commands on your Linux machine. Start by listing all services, then check their status and enablement. With practice, managing Linux services will become second nature, making your system administration smoother and more efficient. ### FAQs ### How do I know if my Linux uses systemd or SysVinit? You can check by running `pidof systemd`. If it returns a process ID, your system uses systemd. Otherwise, it likely uses SysVinit. ### Can I list services without root privileges? Listing services usually requires root or sudo access for full details. Some commands may show limited info without elevated permissions. ### What is the difference between active and enabled services? Active services are currently running. Enabled services are set to start automatically at boot, whether they are running now or not. ### How do I list only failed services? Use `systemctl --failed` to see services that failed to start or crashed. ### Can I list services on remote Linux machines? Yes, by using SSH to connect remotely and running the same commands, you can list services on remote Linux systems.