i@D8LXQt:~$ systemctl --failed
  UNIT            LOAD   ACTIVE SUB    DESCRIPTION
● connman.service loaded failed failed Connection service

LOAD   = Reflects whether the unit definition was properly loaded.
ACTIVE = The high-level unit activation state, i.e. generalization of SUB.
SUB    = The low-level unit activation state, values depend on unit type.

1 loaded units listed. Pass --all to see loaded but inactive units, too.
To show all installed unit files use 'systemctl list-unit-files'.
ti@D8LXQt:~$ systemctl --failed
  UNIT            LOAD   ACTIVE SUB    DESCRIPTION
● connman.service loaded failed failed Connection service

LOAD   = Reflects whether the unit definition was properly loaded.
ACTIVE = The high-level unit activation state, i.e. generalization of SUB.
SUB    = The low-level unit activation state, values depend on unit type.

1 loaded units listed. Pass --all to see loaded but inactive units, too.
To show all installed unit files use 'systemctl list-unit-files'.
ti@D8LXQt:~$ ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000
    link/ether 1c:87:2c:48:99:60 brd ff:ff:ff:ff:ff:ff
ti@D8LXQt:~$ cat /proc/cmdline
BOOT_IMAGE=/boot/vmlinuz-3.16.0-4-amd64 root=UUID=c54d53e9-a17b-4537-8522-3b8cdb83fecb ro initrd=/install/gtk/initrd.gz quiet