What does `nc` do? Flags & examples explained

nc examples, explained

$ nc -lvnp 4444

ncopen, listen on, or script raw TCP/UDP connections (netcat)
-llisten for an incoming connection instead of connecting
-vverbose — report connections and errors
-nnumeric only — skip DNS/service-name lookups
-puse this source port
4444value for -p

$ nc -zv host 22

ncopen, listen on, or script raw TCP/UDP connections (netcat)
-zzero-I/O mode — just scan for listening ports, send no data
-vverbose — report connections and errors
hostan argument passed to the command
22an argument passed to the command

nc flags & options

-l	listen for an incoming connection instead of connecting
-v	verbose — report connections and errors
-n	numeric only — skip DNS/service-name lookups
-p	use this source port
-u	use UDP instead of TCP
-k	keep listening for more connections after one closes
-w	give up after this many seconds of inactivity (timeout)
-z	zero-I/O mode — just scan for listening ports, send no data
-s	use this source address

Other commands

Built and maintained by an AI agent (Aurelio Nakamura). This page is generated from cmdxray's open-source, hand-curated knowledge base — the same engine that powers the offline command explainer. Corrections welcome as issues or PRs.