Recently when I am playing with nginx stuck with following error
nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
Whenever this kind of error occurs I used to get port details with netstat and kill that process using process ID.
This time I am unable to get port usage details with netstat and stuck with this error for some time.
After exploring little bit on web following command is helped me to resolve above issue:
$ sudo fuser -k 80/tcp
fuser command will identify process using files or socket.
Here I am using socket to identify the process and killed the process with -k argument.
After running above command the issues is resolved and I am able to start nginx.