There are a few different ways to do benchmarking and load testing on parts of your web application stack such as the web server, the database, the cache layer etc. This article shows a somewhat comprehensive list of the alternative solutions along with some pros and cons. You are encouraged to explore those more in depth and find the solution that suits you best.
Tmux is a terminal multiplexer, that is a piece of software that allows you access to multiple terminal sessions from a single terminal window. It is extremely useful when doing maintenance on some server via SSH because it will allow you to simultaneously see the output of multiple terminal commands at the same time without having to run multiple ssh sessions.
Recently I had to setup a self signed certificate for a Windows Apache setup. This of course requires the usage of openssl. However openssl returned the following error code when trying to use it: