Lsof

lsof list open files and network connections.

Basic commands

• lsof -t /path/to/file
• lsof /path/to/file
• lsof -p PID
• Open TCP ports: lsof -iTCP -sTCP:LISTEN -P -n
• Open UDP ports:lsof -iUDP -P -n

Activities

• Read lsof questions on StackExchange: https://unix.stackexchange.com/questions/tagged/lsof?tab=Votes

See also

• strace
• netstat

http://man7.org/linux/man-pages/man8/lsof.8.html