Is there a way to extract contents from AppleScript file without using AppleScript editor?
You cannot open a .scpt file with any editor! It is a compiled version of the script, not text, and it will not open with any editor.

Case in point, here is what happens when I try to view the file in Terminal...



OSX comes with osadecompile that will extract the source code of a compiled script .scpt file.

Here is an example...

$ osadecompile args2.scpt 
on run argv
    set argc to 0
    try
        set argc to (count of argv)
    end try
    display dialog ("Argument Count: " &amp; argc as string)
end run