Finding the process that is using a certain port in Linux

You have a couple of options:

lsof -i tcp:80

will give you the list of processes using tcp port 80.

Alternatively,

sudo netstat -nlp

will give you all open network connections.

netstat -lp

I am using "CentOS 7 minimal" which has nor netstat neither lsof. But a lot of linux distributions have the socket statistics command (i.e. ss).

Here is an example of execution:

# ss -tanp | grep 6379
LISTEN   0    128  127.0.0.1:6379   *:*   users:(("redis-server",pid=2531,fd=4))