What does LSOF command do in Linux?

lsof is a command meaning “list open files”, which is used in many Unix-like systems to report a list of all open files and the processes that opened them. This open source utility was developed and supported by Victor A.

How do I know if LSOF is installed?

For finding out all the processes that are currently using a certain port, call “lsof” with the “-i” flag followed by the protocol and port information. For example, to check out all the programs currently accessing port 80 over TCP/IP protocol, run the following command.