tshark is the command counterpart to Wireshark.
It comes with wireshark and should be available if Wireshark is installed

example quick search for flag

tshark -r capture.pcapng -Y 'frame contains "SKY-"' -T fields -e frame.number -e data

tshark — the command-line version of Wireshark for capturing/reading packets

-r capture.pcapng — read from the file capture.pcapng instead of live capturing

-Y 'frame contains "SKY-"' — display filter (like Wireshark's filter bar); only process frames where the raw content contains the string SKY-

-T fields — sets the output format to fields mode, meaning only print the specific fields you ask for (rather than the default summary line)

-e frame.number — extract the frame number field

-e data — extract the raw data field (the payload bytes)