Remove duplicate device from nmcli dev wifi list

Question

Is there a way to remove the duplicate and empty SSIDs?

output of nmcli -f SSID dev wifi

SSID
--
V-ODT
--
V-ODT
--
V-ODT
--
RTU240-156B
fortinet

desired output

SSID
V-ODT
RTU240-156B
fortinet

output of nmcli dev wifi list --rescan yes

IN-USE  BSSID              SSID                          MODE   CHAN  RATE        SIGNAL  BARS  SECURITY        
  03:EC:DA:79:C7:1F  --                            Infra  11    195 Mbit/s  100     ▂▄▆█  WPA2
* 03:EC:DA:79:C7:1E  V-ODT                         Infra  40    540 Mbit/s  94      ▂▄▆█  WPA2     
  07:EC:DA:79:C7:1E  --                            Infra  40    540 Mbit/s  94      ▂▄▆█  WPA2     
  61:22:33:18:20:BE  V-ODT                         Infra  1     260 Mbit/s  84      ▂▄▆█  WPA2     
  63:22:33:18:20:BE  --                            Infra  1     260 Mbit/s  79      ▂▄▆_  WPA2     
  63:22:33:18:20:BF  V-ODT                         Infra  36    540 Mbit/s  59      ▂▄▆_  WPA2     
  63:22:33:28:20:BF  --                            Infra  36    540 Mbit/s  59      ▂▄▆_  WPA2     
  01:1E:42:3C:16:6B  RUT240_156B                   Infra  8     65 Mbit/s   57      ▂▄▆_  WPA2      
  05:D5:90:E7:5A:60  fortinet                      Infra  1     195 Mbit/s  30      ▂___  WPA2

Answer 1

You can pipe the output through sort and uniq. uniq filters duplicates, but requires the input to be sorted.

To filter the --, use grep. However, Unix commands use hyphens to indicate options. When they should treat something starting with a hyphen as non-option arguments, the convention is to add -- to indicate the end of the options. So you need to add -- twice to grep here, once to signal the end of the options, and once for what you actually want to filter.

nmcli -f SSID dev wifi | sort | uniq | grep -v -- --