Debian/Ubuntu

cat /etc/X11/default-display-manager

RedHat (ka Fedora)

cat /etc/sysconfig/desktop

openSUSE

cat /etc/sysconfig/displaymanager

systemd puhul

# 1.võimalus
grep '/usr/s\\?bin' /etc/systemd/system/display-manager.service

# vastus näiteks
ExecStart=/usr/bin/mdm

# 2.võimalus
systemctl status display-manager

● sddm.service - Simple Desktop Display Manager
     Loaded: loaded (/usr/lib/systemd/system/sddm.service; enabled; vendor preset: disabled)
     Active: active (running) since Sat 2021-11-13 16:57:05 EET; 1h 2min ago
       Docs: man:sddm(1)
             man:sddm.conf(5)
   Main PID: 620 (sddm)
      Tasks: 8 (limit: 18844)
     Memory: 134.6M
        CPU: 1min 56.249s

# 3.võimalus
systemctl |grep "Display Manager"

sddm.service       loaded active running   Simple Desktop Display Manager

# 4.võimalus
file /etc/systemd/system/display-manager.service

/etc/systemd/system/display-manager.service: symbolic link to /usr/lib/systemd/system/sddm.service

# 5.võimalus
systemctl --property=Id,Description show display-manager.service

Id=sddm.service
Description=Simple Desktop Display Manager

Näiteks on võimalus kuvahalduri teenust taaskäivitada ja seeläbi uuesti sisse logida:

sudo systemctl restart display-manager