In this guide, you are going to learn how to list running services on Linux System. After boot process in Linux System, it enters final system initialization,where it needs to start various services. A service, or daemon, is a program that performs a particular duty. init is the initialization daemon determines which services are started and in what order.
There are various initialization systems in Linux;
System V: A service manager based on the SysVinit standard controls which daemons and resources will be available by employing the concept ofrunlevels.Systemd: systemd is a modern system and services manager with a compatibility layer for the SysV commands and runlevels. It has a concurrent structure, employs sockets and D-Bus for service activation, on-demand daemon execution, process monitoring with cgroups, snapshot support, system session recovery, mount point control and a dependency-based service control.- There was
Upstartalso. Upstart is an event-based replacement for the /sbin/init daemon which handles starting of tasks and services during boot, stopping them during shutdown and supervising them while the system is running.
Checking System Manager running on the System
In recent years most major Linux distributions have gradually adopted systemd as their default system manager while SysV and Upstart are not used by many major Linux distributions anymore.
Finding the location of the init using which command;
which init
/usr/sbin/initThe location of init program file is /usr/sbin directory. You can use readlink -f command with super user privileges to check if the program is linked to another program.
sudo readlink -f /usr/sbin/init
/usr/lib/systemd/systemdAccording to the above output, you find that the init program file is linked to systemd.
Check init system using file command
To use file command to find the init system, simply run;
file /sbin/init
/sbin/init: symbolic link to /lib/systemd/systemdCheck init system with ps Utility
ps utility allows you to view processes. A process is a running program, we can use ps utility to determine the first (1) program loaded after the boot process.
ps -p 1
PID TTY TIME CMD
1 ? 00:00:03 systemdIn the above output, the systemd program is running. Thus, the Linux system is using systemd.
Checking with pstree Utility
Another way to check the system manger is using pstree command, pipe (|) the command to head -n 4 command to display first four lines of pstree i.e
pstree | head -n 4
systemd-+-ModemManager---2*[{ModemManager}]
|-NetworkManager---2*[{NetworkManager}]
|-accounts-daemon---2*[{accounts-daemon}]
|-acpidAs you can see in the above output, we obtain systemd meaning that the system manger is systemd. but if you obtain init, it means that the system is running SysVinit.
Listing Running Services on Systemd
The systemctl utility is the main gateway to managing systemd and system services.
Syntax;
systemctl [OPTIONS…] COMMAND [NAME…]
Exploring systemd is through the systemd units. A unit defines a service, a group of services, or an action. There are currently 12 main different systemd unit types:
- automount
- device
- mount
- path
- scope
- service
- slice
- snapshot
- socket
- swap
- target
- timer
Listing various loaded Units
Using systemctl command we can provide a list of the various units currently loaded in the Linux system.
systemctl list-units
UNIT LOAD ACTIVE SUB DESCRIPTION >
proc-sys-fs-binfmt_misc.automount loaded active waiting Arbitrary Executable File Formats File System Aut>
sys-devices-pci0000:00-0000:00:02.0-drm-card0-card0\x2dLVDS\x2d1-intel_backlight.device loaded active plugged /sys/devices/pci0000:00/0000:00:02.0/drm/card0/ca>
sys-devices-pci0000:00-0000:00:1a.0-usb1-1\x2d1-1\x2d1.2-1\x2d1.2:1.0-net-usb0.device loaded active plugged TECNO_CAMON_12 >
sys-devices-pci0000:00-0000:00:1a.0-usb1-1\x2d1-1\x2d1.3-1\x2d1.3:1.0-bluetooth-hci0.device loaded active plugged /sys/devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1>
sys-devices-pci0000:00-0000:00:1b.0-sound-card0.device loaded active plugged 7 Series/C216 Chipset Family High Definition Audi>
sys-devices-pci0000:00-0000:00:1c.0-0000:01:00.0-net-enp1s0.device loaded active plugged AR8162 Fast Ethernet >
sys-devices-pci0000:00-0000:00:1c.1-0000:02:00.0-net-wlp2s0.device loaded active plugged AR9285 Wireless Network Adapter (PCI-Express) >
sys-devices-pci0000:00-0000:00:1f.2-ata1-host0-target0:0:0-0:0:0:0-block-sda-sda1.device loaded active plugged ST500LM012_HN-M500MBB 1 >Listing all loaded Services
Use the list-units command and --type switch with a value “service” to list all loaded services on your system. it will list all active services.
systemctl list-units --type=service
UNIT LOAD ACTIVE SUB DESCRIPTION
accounts-daemon.service loaded active running Accounts Service
acpid.service loaded active running ACPI event daemon
alsa-restore.service loaded active exited Save/Restore Sound Card State
apache2.service loaded active running The Apache HTTP Server
apparmor.service loaded active exited Load AppArmor profiles
apport.service loaded active exited LSB: automatic crash report generation
avahi-daemon.service loaded active running Avahi mDNS/DNS-SD Stack
blk-availability.service loaded active exited Availability of block devices
bluetooth.service loaded active running Bluetooth service
colord.service loaded active running Manage, Install and Generate Color Profiles
console-setup.service loaded active exited Set console font and keymap
cron.service loaded active running Regular background program processing daemon
cups-browsed.service loaded active running Make remote CUPS printers available locally
cups.service loaded active running CUPS Schedulersystemctl --type=service will produce the same output.
To see all loaded active and inactive units pass --all switch to systemctl list-units –type=service command i.e.
systemctl list-units --type=service --all
UNIT LOAD ACTIVE SUB DESCRIPTION
accounts-daemon.service loaded active running Accounts Service
acpid.service loaded active running ACPI event daemon
alsa-restore.service loaded active exited Save/Restore Sound Card State
alsa-state.service loaded inactive dead Manage Sound Card State (restore and store)
anacron.service loaded inactive dead Run anacron jobs
apache2.service loaded active running The Apache HTTP Server
apparmor.service loaded active exited Load AppArmor profiles
apport-autoreport.service loaded inactive dead Process error reports when automatic reporting is enabled
apport.service loaded active exited LSB: automatic crash report generation
apt-daily-upgrade.service loaded inactive dead Daily apt upgrade and clean activities
apt-daily.service loaded inactive dead Daily apt download activities
● auditd.service not-found inactive dead auditd.service
auth-rpcgss-module.service loaded inactive dead Kernel Module supporting RPCSEC_GSS
avahi-daemon.service loaded active running Avahi mDNS/DNS-SD Stack
blk-availability.service loaded active exited Availability of block devices
bluetooth.service loaded active running Bluetooth service
colord.service loaded active running Manage, Install and Generate Color Profiles
● connman.service not-found inactive dead connman.service
● console-screen.service not-found inactive dead console-screen.service
console-setup.service loaded active exited Set console font and keymap
cron.service loaded active running Regular background program processing daemon
cups-browsed.service loaded active running Make remote CUPS printers available locally
cups.service loaded active running CUPS Scheduler
dbus.service loaded active running D-Bus System Message Bus
dm-event.service loaded inactive dead Device-mapper event daemon
dmesg.service loaded inactive dead Save initial kernel messages after boot
e2scrub_all.service loaded inactive dead Online ext4 Metadata Check for All Filesystems
e2scrub_reap.service loaded inactive dead Remove Stale Online ext4 Metadata Check Snapshots
emergency.service loaded inactive dead Emergency Shell
● fcoe.service not-found inactive dead fcoe.service
fstrim.service loaded inactive dead Discard unused blocks on filesystems from /etc/fstabListing all Services by State
To list services by state, use --state option with the value active, inactive, running, dead services in the system.
Active Services
Use the following command to obtain active service.
systemctl --type=service --state=active
UNIT LOAD ACTIVE SUB DESCRIPTION
accounts-daemon.service loaded active running Accounts Service
acpid.service loaded active running ACPI event daemon
alsa-restore.service loaded active exited Save/Restore Sound Card State
apache2.service loaded active running The Apache HTTP Server
apparmor.service loaded active exited Load AppArmor profiles
apport.service loaded active exited LSB: automatic crash report generation
avahi-daemon.service loaded active running Avahi mDNS/DNS-SD Stack
blk-availability.service loaded active exited Availability of block devices
bluetooth.service loaded active running Bluetooth service
colord.service loaded active running Manage, Install and Generate Color Profiles
console-setup.service loaded active exited Set console font and keymap
cron.service loaded active running Regular background program processing daemon
cups-browsed.service loaded active running Make remote CUPS printers available locally
cups.service loaded active running CUPS Scheduler
dbus.service loaded active running D-Bus System Message BusInactive Services
Use the following command to obtain inactive service.
systemctl --type=service --state=inactive
UNIT LOAD ACTIVE SUB DESCRIPTION
alsa-state.service loaded inactive dead Manage Sound Card State (restore and store)
anacron.service loaded inactive dead Run anacron jobs
apport-autoreport.service loaded inactive dead Process error reports when automatic reporting is enabled
apt-daily-upgrade.service loaded inactive dead Daily apt upgrade and clean activities
apt-daily.service loaded inactive dead Daily apt download activities
● auditd.service not-found inactive dead auditd.service
auth-rpcgss-module.service loaded inactive dead Kernel Module supporting RPCSEC_GSS
● connman.service not-found inactive dead connman.service
● console-screen.service not-found inactive dead console-screen.service
dm-event.service loaded inactive dead Device-mapper event daemon
dmesg.service loaded inactive dead Save initial kernel messages after boot
e2scrub_all.service loaded inactive dead Online ext4 Metadata Check for All Filesystems
e2scrub_reap.service loaded inactive dead Remove Stale Online ext4 Metadata Check Snapshots
emergency.service loaded inactive dead Emergency Shell
● fcoe.service not-found inactive dead fcoe.service
fstrim.service loaded inactive dead Discard unused blocks on filesystems from /etc/fstab
fwupd-refresh.service loaded inactive dead Refresh fwupd metadata and update motd
getty-static.service loaded inactive dead getty on tty2-tty6 if dbus and logind are not availableRunning Services
Use the following command to obtain running service.
systemctl --type=service --state=running
UNIT LOAD ACTIVE SUB DESCRIPTION
accounts-daemon.service loaded active running Accounts Service
acpid.service loaded active running ACPI event daemon
apache2.service loaded active running The Apache HTTP Server
avahi-daemon.service loaded active running Avahi mDNS/DNS-SD Stack
bluetooth.service loaded active running Bluetooth service
colord.service loaded active running Manage, Install and Generate Color Profiles
cron.service loaded active running Regular background program processing daemon
cups-browsed.service loaded active running Make remote CUPS printers available locally
cups.service loaded active running CUPS Scheduler
dbus.service loaded active running D-Bus System Message Bus
gdm.service loaded active running GNOME Display Manager
irqbalance.service loaded active running irqbalance daemon
kerneloops.service loaded active running Tool to automatically collect and submit kernel crash signatures
libvirtd.service loaded active running Virtualization daemon
ModemManager.service loaded active running Modem Manager
mysql.service loaded active running MySQL Community Server
networkd-dispatcher.service loaded active running Dispatcher daemon for systemd-networkd
NetworkManager.service loaded active running Network ManagerDead Services
Use the following command to obtain dead service.
systemctl --type=service --state=dead
UNIT LOAD ACTIVE SUB DESCRIPTION
alsa-state.service loaded inactive dead Manage Sound Card State (restore and store)
anacron.service loaded inactive dead Run anacron jobs
apport-autoreport.service loaded inactive dead Process error reports when automatic reporting is enabled
apt-daily-upgrade.service loaded inactive dead Daily apt upgrade and clean activities
apt-daily.service loaded inactive dead Daily apt download activities
● auditd.service not-found inactive dead auditd.service
auth-rpcgss-module.service loaded inactive dead Kernel Module supporting RPCSEC_GSS
● connman.service not-found inactive dead connman.service
● console-screen.service not-found inactive dead console-screen.service
dm-event.service loaded inactive dead Device-mapper event daemon
dmesg.service loaded inactive dead Save initial kernel messages after boot
e2scrub_all.service loaded inactive dead Online ext4 Metadata Check for All Filesystems
e2scrub_reap.service loaded inactive dead Remove Stale Online ext4 Metadata Check Snapshots
emergency.service loaded inactive dead Emergency Shell
● fcoe.service not-found inactive dead fcoe.serviceListing Running Services on SysVinit
To view a SysVinit managed service’s status and control whether it is currently running, use the service utility.
Syntax;
service SCRIPT COMMAND [OPTIONS]
If you are using SysV system manager, to list all services in the system use service --status-all command i.e
service --status-all
[ + ] acpid
[ - ] alsa-utils
[ - ] anacron
[ - ] apache-htcacheclean
[ + ] apache2
[ + ] apparmor
[ + ] apport
[ + ] avahi-daemon
[ + ] bluetooth
[ - ] console-setup.sh
[ + ] cron
[ + ] cups
[ + ] cups-browsed
[ + ] dbusIn the above output, the symbols means;
+ :means that the service is running.– :means that the service is not running at all.
Although some SysVinit commands have been modified to work with systemd utilities, others, such as service --status-all, might produce unpredictable or confusing results.
This marks the end of our guide on how list running services on Linux. Stay tuned for more guides. Hope this guide has been helpful.
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