4.25. How do I join two lines if line #1 ends in a [certain string]?
This question appears in the section on one-line sed scripts, but
it comes up so many times that it needs a place here also. Suppose
a line ends with a particular string (often, a line ends with a
backslash). How do you bring up the second line after it, even in
cases where several consecutive lines all end in a backslash?
sed -e :a -e '/\\$/N; s/\\\n//; ta' file # all seds
sed ':a; /\\$/N; s/\\\n//; ta' file # GNU sed, ssed, HHsed
Note that this replaces the backslash-newline with nothing. You may
want to replace the backslash-newline with a single space instead.