Replace all lfs not preceeded by cr with cr+lf: 
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}

In reply to Re: Clean line ends by shmem
in thread Clean line ends by Scarborough

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