I am using prelude as a base Emacs configuration. I have installed lots of packages from the package manager, and I want to use my settings on another machine.
I don't want to carry the installed packages and also I don't want to create a list manually.
What is the way of saving a list all the installed packages into prelude-package.el or any other file so that when I take this configuration to my other machine, they automatically get installed there on first use?
You can get a list of currently installed packages (excluding built in packages) from the variable package-activated-list. To automatically install them on startup, see this question: how to automatically install emacs packages by specifying a list of package names?
More specifically, if you do C-h v package-activated-list, copy the value shown, and insert it as the value of prelude-packages, emacs will automatically ensure those packages are installed on start up.