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- Title (e.g., "How to List Services in Linux: A Practical Guide")
- Rationale (e.g., Explaining why knowing how to list services is important for system administration)
- Suggested Hook (e.g., Starting with a scenario where a system admin needs to troubleshoot system services)
Meanwhile, I’ll assume a general approach based on the topic and write a practical how-to blog post on listing services in Linux.
How to List Services in Linux: A Practical How-To Guide
Rationale:
Managing services on a Linux system is a crucial task for sysadmins and power users. Whether you’re troubleshooting a malfunctioning service or simply auditing which services are enabled on your server, knowing how to effectively list and manage services is fundamental.
Hook:
Imagine you’ve just deployed a new web server, but your website isn’t accessible. The first step is to check if the web service (like Apache or Nginx) is actually running and enabled to start at boot. Knowing how to quickly list and inspect services can save hours of frustration.
What Are Services in Linux?
Services (also called daemons) are background processes that run continuously or start on-demand to provide core functionality—think web servers, database engines, cron jobs, SSH access, and more.
Understanding which services are active and their statuses helps maintain system health and security.
How to List Services in Linux
Linux distributions use different init systems by default. The two most common are:
- systemd (used by most modern distros like Ubuntu 16.04+, CentOS 7+, Debian 8+)
- SysVinit or Upstart (older systems)
1. Listing Services with systemd (systemctl)
For modern Linux distros using systemd, systemctl is your go-to command.
List All Installed Services
systemctl list-unit-files --type=service
This will display all installed service unit files along with their enabled/disabled status.
Example output snippet:
apache2.service enabled
cron.service enabled
ssh.service enabled
bluetooth.service disabled
List Active (Running) Services
To see only currently running services:
systemctl list-units --type=service --state=running
Example output:
UNIT LOAD ACTIVE SUB DESCRIPTION
cron.service loaded active running Regular background program processing daemon
ssh.service loaded active running OpenSSH Daemon
Check Status of a Specific Service
Want to know about one particular service? Use
systemctl status apache2.service
This gives detailed info about the service's state, logs, and any errors.
2. Listing Services in SysVinit Systems
If your Linux distro uses SysVinit or older init systems:
List All Available Services
service --status-all
This outputs a list like:
[ + ] ssh
[ - ] apache2
[ ? ] bluetooth
+ means running; - means stopped; ? unknown.
Check Status of Specific Service
service apache2 status
3. Using chkconfig on Some Distributions
In some Red Hat-based distros,
chkconfig --list
shows which services are configured at different runlevels.
Bonus: Using ps or top for Active Processes
Although not listing "services" per se,
ps aux | grep service-name
helps check if the daemon process is alive.
For example:
ps aux | grep nginx
Will output lines indicating whether nginx worker processes are running.
Summary Cheat Sheet for Common Commands
| Purpose | Command |
|---|---|
| List all installed services | systemctl list-unit-files --type=service |
| List all active/running | systemctl list-units --type=service --state=running |
| Check single service status | systemctl status <service> / service <name> status |
| List SysVinit service statuses | service --status-all |
| List runlevel configuration | chkconfig --list |
Wrapping Up
Listing services on Linux is straightforward once you know the commands tailored for your distribution’s init system. Mastering these helps you quickly diagnose problems or audit that your critical services are running as intended.
Try these commands out on your machine today—it’s an essential skill that will make managing Linux systems less of a mystery!
If you'd like me to tailor this content further once you provide the title and rationale, just let me know!