Tshark custom grep

So my command is:

tshark -Y 'wlan.fc.type_subtype==0x04'

So my output is:

21401 205.735966 Apple_90:ea:8e -> Broadcast    802.11 155 Probe Request, SN=3667, FN=0, Flags=........C, SSID=Broadcast

How can I get Apple_90:ea:8e + SSID=Broadcast and whats the logic behind the grep? Is it possible with grep?

Considering that: Apple_90:ea:8e and Broadcast will always change!

Answer

$ var='21401 205.735966 Apple_90:ea:8e -> Broadcast    802.11 155 Probe Request, SN=3667, FN=0, Flags=........C, SSID=Broadcast'
$ grep -oP 'S+(?= ->)|SSID=S+' <<< "$var"
Apple_90:ea:8e
SSID=Broadcast

The grep option -o says “only return what was matched, not the whole line” and -P is to use the Perl regex engine (because we use look-arounds). The regex is

S+       # One or more non-spaces
(?= ->)   # followed by " ->"
|         # or...
SSID=S+  # "SSID=" and one or more non-spaces