Systemd Cheat Sheet

#systemd Core Utilities

systemd utility List

Utility	Description
`systemctl`	Manages services (start, stop, restart, enable, disable, etc.)
`journalctl`	Views and filters logs collected by the systemd journal
`loginctl`	Manages user logins and sessions
`hostnamectl`	Sets or queries the hostname and related machine metadata
`timedatectl`	Sets or queries the system date, time, and NTP settings
`systemd-analyze`	Analyzes system boot-up performance
`systemd-cgtop`	Monitors control group resource usage in real time
`systemd-run`	Runs a command as a transient service or scope
`resolvectl`	Resolves domain names using the systemd-resolved service
`busctl`	Interacts with the D-Bus message bus system

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#Utility Commands

systemctl

systemctl - System Commands

Manage systemd units and control system services (start, stop, enable, etc.).

Command	Description
`systemctl halt`	Stop all running software, leave the hardware powered on.
`systemctl hibernate`	Save contents of system memory to disk and power off the hardware.
`systemctl poweroff`	Halt and power off the system.
`systemctl reboot`	Reboot the system.

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systemctl - Service Commands

Command	Description
`systemctl start <service>`	Start a service immediately
`systemctl stop <service>`	Stop a running service
`systemctl restart <service>`	Restart a service
`systemctl reload <service>`	Reload service configuration without restart
`systemctl enable <service>`	Enable service to start at boot
`systemctl disable <service>`	Disable boot-time start
`systemctl status <service>`	Show current status and recent logs
`systemctl mask <service>`	Prevent service from being started
`systemctl unmask <service>`	Remove mask so it can start again
`systemctl list-units`	List active units
`systemctl list-unit-files`	List all unit files and their enabled state

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journalctl

Query and filter logs from the systemd journal.

Command	Description
`journalctl`	Show entire journal
`journalctl -b`	Show logs from current boot
`journalctl --list-boots`	List all boot sessions
`journalctl -b -1`	Logs from previous boot
`journalctl -u <service>`	Show logs for a specific unit/service
`journalctl -n 100`	Show the last 100 log entries
`journalctl -f`	Follow new log entries (tail -f style)
`journalctl -p err..emerg`	Show only error (and above) priority logs
`journalctl --disk-usage`	Show disk usage of journal
`journalctl --since today`	Show logs since today

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busctl

Inspect and monitor D-Bus (Desktop Bus) for debugging or introspection.

Command	Description
`busctl list`	List all services/peers on the bus
`busctl status [SERVICE\|PID]`	Show process info & credentials for service or PID
`busctl monitor [SERVICE...]`	Dump live message traffic, Ctrl+C to stop
`busctl capture [SERVICE...]`	Capture bus traffic to a pcap file
`busctl tree [SERVICE...]`	Show object tree exported by service(s)

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loginctl

Manages user sessions and login-related settings.

Command	Description
`loginctl list-sessions`	List all active sessions
`loginctl list-users`	List logged-in users
`loginctl user-status <UID>`	Show all sessions & processes for user `<UID>`
`loginctl session-status <ID>`	Show detailed info and logs for session `<ID>`
`loginctl show-session <ID>`	Show machine-parsable properties of a session
`loginctl terminate-session <ID>`	End all processes in session `<ID>`
`loginctl lock-session <ID>`	Lock the specified session
`loginctl unlock-session <ID>`	Unlock the specified session

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systemd-analyze

Analyze system boot performance and unit dependencies.

Command	Description
`systemd-analyze`	Show total boot time breakdown
`systemd-analyze blame`	List services ordered by startup time
`systemd-analyze plot > boot.svg`	Generate SVG visual of boot sequence

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systemd-cgtop

Real-time monitoring of resource usage by cgroups (CPU, memory, I/O).

Command	Description
`systemd-cgtop`	Monitor top cgroups resource usage
`systemd-cgtop -c`	Sort cgroups by CPU usage
`systemd-cgtop -d <delay>`	Change refresh delay interval

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timedatectl

Manage system date, time, timezone, and NTP synchronization.

Command	Description
`timedatectl status`	Show current date/time settings
`timedatectl list-timezones`	List all available timezones
`timedatectl set-timezone <Zone>`	Set system timezone
`timedatectl set-time "YYYY-MM-DD"`	Manually set date
`timedatectl set-time "HH:MM:SS"`	Manually set time
`timedatectl set-ntp true`	Enable NTP sync
`timedatectl set-ntp false`	Disable NTP sync

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resolvectl

Interact with systemd-resolved DNS resolver service.

Command	Description
`resolvectl status`	Show DNS configuration and link info
`resolvectl query <hostname>`	Resolve hostname via systemd-resolved
`resolvectl dns <interface> <IP>`	Set DNS server(s) for a specific interface
`resolvectl domain <interface> <name>`	Set search domain(s) for an interface
`resolvectl flush-caches`	Clear the DNS cache managed by systemd-resolved
`resolvectl reset-statistics`	Reset all DNS resolution statistics

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hostnamectl

Query and set the system hostname (static, transient, pretty) and related metadata.

↓ Commands

Command	Description
`hostnamectl status`	Show current hostname & system info
`hostnamectl hostname <NAME>`	Set the static/transient/pretty hostname
`hostnamectl set-hostname <NAME> --static`	Set only the static hostname
`hostnamectl set-hostname <NAME> --transient`	Set only the transient hostname
`hostnamectl set-hostname <NAME> --pretty`	Set the pretty (user-friendly) hostname
`hostnamectl set-chassis <TYPE>`	Set chassis type (e.g., desktop, laptop, server)

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↓ Description

- Static - The permanent hostname stored in `/etc/hostname`. Used at boot time.
- Transient - Temporary hostname set at runtime (often by DHCP or manually). Lost on reboot.
- Pretty - A user-friendly, display name (can include spaces and special characters).

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systemd-run

Run a command as a transient systemd unit (service, scope, timer, etc.).

Command	Description
`systemd-run <command>`	Run command as a transient `.service` unit
`systemd-run -p BlockIOWeight=10 updatedb`	Run with a specific resource limit property
`systemd-run -p MemoryMax=100M script.sh`	Run a memory-hungry task with a memory usage limit
`systemd-run --on-calendar='YYYY-MM-DD HH:MM' script.sh`	Schedule script to run at a specific date and time
`systemd-run -E VAR=value script.sh`	Run a script with environment variables set

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Types of systemd limits{.col-span-3}

There are different kinds of limit that can be imposed:

- CPU Limits
- Memory Limits
- I/O Limits
- Task/Thread Limits
- Security/Isolation
- Execution/Environment

Example

systemd-run -p MemoryMax=100M -p CPUQuota=50% scriptFile.sh

Systemd CHEAT SHEET

#systemd Core Utilities

#Utility Commands

systemctl - System Commands

systemctl - Service Commands

↓ Commands

↓ Description

Types of systemd limits{.col-span-3}

#Also See