How can I have tcpdump write to file and standard output the appropriate data?
Here's a neat way to do what you want:
tcpdump -w - | tee somefile | tcpdump -r -
What it does:
-
-w -tellstcpdumpto write binary data tostdout -
teewrites that binary data to a file AND to its ownstdout -
-r -tells the secondtcpdumpto get its data from itsstdin
Since tcpdump 4.9.3 4.99.0, the --print option can be used:
tcpdump -w somefile --print
Wednesday, December 30, 2020, by [email protected], denis and fxl.
Summary for 4.99.0 tcpdump release
[...]
User interface:
[...]
Add --print, to cause packet printing even with -w.