Q:

How do I know which MongoDB version is installed by using the Command Line?

Without changing directory to \MongoDB\bin\, when I call:
mongod -v

I get:
'mongod' is not recognized as an internal or external command, operable
program or batch file.

When I call the same command from \bin\ it launches the server just like I'm calling:
mongod

It is the same case with 'mongo' and 'mongos'.
I added the \bin\ path to the environment variables thinking it will help but it didn't.
To clarify with an example, to get the version of Ruby, I can call:
ruby -v

Why can't I do the same with MongoDB?

A:

First add location of MongoDB's bin folder to PATH env variable. This is required because it is the place where mongod.exe is stored.
For example, if MongoDB 4.0 is in your Program Files, add "C:\Program Files\MongoDB\Server\4.0\bin" to PATH for all system users.
Then try using :
mongod --version

