On macOS you can read and write to the clipboard with pbcopy and pbpaste:

    $ ls | pbcopy

    $ pbpaste > out.txt

You can also put this in a function in order to get the path of the frontmost Finder window:

    osascript 2>/dev/null -e '
      tell application "Finder"
        return POSIX path of (target of window 1 as alias)
      end tell'

Get the current Finder selection:

    osascript 2>/dev/null -e '
      set output to ""
      tell application "Finder" to set the_selection to selection
      set item_count to count the_selection
      repeat with item_index from 1 to count the_selection
        if item_index is less than item_count then set the_delimiter to "\n"
        if item_index is item_count then set the_delimiter to ""
        set output to output & ((item item_index of the_selection as alias)\'s POSIX path) & the_delimiter
      end repeat'