Edit File: insert-header.sin
# 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 }