systemctl edit

Create unit overrides

medium risk

interactive breakdown — edit the command and press Explain
$ 
⚠ Risks & cautions
What it does

Creates /etc/systemd/system/<unit>.d/override.conf.

Examples
systemctl edit nginxEdit a drop-in · explain & risk-check →
systemctl cat nginxShow the effective unit · explain & risk-check →
Related
systemctl
Open the full explainer →More in System & Processes

Reference text is hand-written and may be incomplete — check man systemctl for your version. Test destructive commands on a non-production system first.