# 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

}