systemctl list-units or systemctl list-units --all
もしくは
systemctl status {service}
or
systemctl cat {service}
で表示できる。
参考
https://www.digitalocean.com/community/tutorials/how-to-use-systemctl-to-manage-systemd-services-and-units
https://help.sakura.ad.jp/hc/ja/articles/206376941-OS%E3%82%BB%E3%83%83%E3%83%88%E3%82%A2%E3%83%83%E3%83%97%E6%83%85%E5%A0%B1-CentOS-7-
