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: " & argc as string)
end run