Originally Posted by JSWolf
Why is it that the text has -- instead of — when that is something that can be done in a text file?
PG produces ASCII text files; the emdash is not a part of the ASCII character set.
ASCII consists of the character codes 0-127, which are standardised. Characters in the range 128-255 vary according to which "code page" one is using; the emdash character you quote above displays correctly in the "Latin 1" code page which most English-speaking countries, and much of western Europe, uses, but it will not display correctly in other code pages.
As an experiment, try viewing this message, in which there is a quoted emdash, if other code pages. If you're using Internet Explorer, go to the "View" menu, select "Encoding", and try some of the other settings such as "Central European"; you'll find that the emdash does not display correctly.