Trying to find the best way to append a file at the end of the other

gistfile1.txt

body common control
{
bundlesequence => { "biginsert" };
inputs => { "cfengine_stdlib.cf" };
}

body agent control
{
editfilesize => "1M";
}

bundle agent biginsert
{
files:
  # I remove the file for testing purpose
  # to prevent every growing file
  "/tmp/bigfile"
        delete => tidy,
        classes => if_ok("file_deleted");
  file_deleted::
  "/tmp/bigfile"
        edit_line => big_edit("/tmp/bigdata"),
        create => "true";
}

bundle edit_line big_edit(content_from_file)
{
 insert_lines:
   "$(content_from_file)"
     insert_type => "file";
}