Search & Replace with lf and/cr

[Richmond]

This is a really hard nut to crack:

I have a very long script that features lines that end like this:

& numToChar(2325))

and lines that end like this

& numToChar(2325))

the top example is followed by a line that starts with "set",
and the lower example is followed by "break":

& numToChar(2325))
set

& numToChar(2325))
break

now I want to "mess around with" the lower type of script line and NOT
the upper one.

AS the script contains somewhere over 5000 lines, and about 50 of those 
sort of lines
that need to be operated on I don't feel a high level of motivation to 
go through
the thing line by line . . .

. . . if I have to I will (the blasted thing is mission critical) . . .

Tried to do the above in LibreOffice and as soon as I pasted the lower
phrase into the search box it turned the thing into

& numToChar(2325)) break

i.e. stripped out the linefeed. Obviously that is no good.

I would be extremely grateful for any constructive help.

[ for choice I would prefer to work on Linux; however I have access to 
Mac 10.6 and Windows XP and 7 should the need arise ].

Richmond.