You can show the result of an expressions in *Shell Command Output* with

(shell-command "date") ;; assuming you're working on *nix

To evaluate an (expression) place marker after it and pressC-x C-e. The message area will display the exist status as 0 if the command is successful and the result will go to *Shell Command Output*.

Now suppose you want to copy the result of the date to your clipboard to be used by emacs. You can do the following

(kill-new (replace-regexp-in-string "\n" "" (shell-command-to-string "date")))

This will add it to the kill ring, an emacs term for the rotating clipboard (it also has another clipboard mechanism called registers). Press C-y to paste from the kill ring

Wed Jan 17 15:23:45 +03 2024

You can number the org files in your directory without opening a command line

(kill-new (shell-command-to-string "wsl ls *.org | nl")) ;; assuming you're on Windows