Look for lines that start with a line feed (ctrl-J) and convert it to a carriage return (ctrl-M) followed by a line feed.

The following is a command line script to do it. It edits your file in place and renames the original version with a .bak extension.

perl -i.bak -pe 's/^\cJ/\cM\cJ/' your_file_name_here
[download]

perl -pi.bak -e 's/(?<!\r)\n/\r\n/' cobolfile
[download]

See perlre.

--shmem

update: as davorg pointed out, it is better to use control chars for newline conversions. The look-behind assertion above replaces bogus newlines elsewhere, not only at blank lines.

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}

I'm sure that works.

But I find I sometimes get confused about how Perl inteprets \n (sometimes it's \012 and sometimes it's \015\012 - see perlport for the details). In order to minimise my confusion I find it helpful to always refer to the control characters (\cJ and \cM) or the numeric character codes (\012 and \015) when I'm converting newline characters.

--
<http://dave.org.uk>

"The first rule of Perl club is you do not talk about Perl club."
-- Chip Salzenberg

I also found David Cross' explanation of differing line end chars very helpful. See his book "Data Munging w/Perl", page 88-89. The topic is very well explained and it was an eye-opener to me when I was confused about new lines for different platforms. Sorry to point you to a book but I think David's book is excellent and his coverage of this particular topic is helpful.