lsof — open files and ports of processes

Cheat sheet

• sudo lsof -i :5432 -nP who's on this port
• sudo lsof +D /dir who holds a directory
• sudo lsof +L1 deleted but open files
• sudo lsof -p 1234 | wc -l how many fds a process has (a leak?)
• sudo kill $(sudo lsof -t -i:8080) kill whoever holds a port

Options

Option	Meaning
-i [:port]	network sockets (optionally by port/host)
-nP	skip DNS and port-name resolution (fast, numeric)
-p PID	files of a specific process
-c name	processes by command name
-u user	by user
+D /dir	recursively, everything under a directory (what's holding the fs)
+L1	files with fewer than 1 link (deleted but still open)
-t	just PIDs (for scripts: kill $(lsof -t ...))