| h | |
| :b | |
| # On the last line, print and exit | |
| $b | |
| N | |
| /^\(.*\)\n\1$/ { | |
| # The two lines are identical. Undo the effect of | |
| # the n command. | |
| g | |
| bb | |
| } | |
| # If the @code{N} command had added the last line, print and exit | |
| $b | |
| # The lines are different; print the first and go | |
| # back working on the second. | |
| P | |
| D |