-# Sed script that inserts the file called HEADER before the header entry.
-#
-# At each occurrence of a line starting with "msgid ", we execute the following
-# commands. At the first occurrence, insert the file. At the following
-# occurrences, do nothing. The distinction between the first and the following
-# occurrences is achieved by looking at the hold space.
-/^msgid /{
-x
-# Test if the hold space is empty.
-s/m/m/
-ta
-# Yes it was empty. First occurrence. Read the file.
-r HEADER
-# Output the file's contents by reading the next line. But don't lose the
-# current line while doing this.
-g
-N
-bb
-:a
-# The hold space was nonempty. Following occurrences. Do nothing.
-x
-:b
-}