,address2]]nRead next line of input into pattern space.  The current line is sent to standard output, and the next line becomes the current line. Control passes to the command following n instead of resuming at the top of the script.
In the ms macros, a section header occurs on the line below an .NH macro.  To print all lines of header text, invoke this script with sed -n:
/^\.NH/{
n
p
}