apt install netcat-openbsd

nc -6

nc -vz -w 3 smilx.cn 1-100

nc -vnz -w 3 192.168.2.1 1-100

nc -vl 666

nc -vn 192.168.2.1 666

nc -vlu 666

nc -vnu 192.168.2.1 666

nc -vl 666 < test.txt

nc -vn 192.168.2.1 666 > text.txt