$foo =~ tr/\cM\cJ//d ; # remove all platforms version of a newline ..
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From perldoc perlop :
All systems use the virtual ""\n"" to represent a line terminator, called a "newline". There is no such thing as an unvarying, physical newline character. It is only an illusion that the operating system, device drivers, C libraries, and Perl all conspire to preserve. Not all systems read ""\r"" as ASCII CR and ""\n"" as ASCII LF. For example, on a Mac, these are reversed, and on systems without line terminator, printing ""\n"" may emit no actual data. In general, use ""\n"" when you mean a "new­ line" for your system, but use the literal ASCII when you need an exact character. For example, most networking protocols expect and prefer a CR+LF (""\015\012"" or ""\cM\cJ"") for line terminators, and although they often accept just ""\012"", they seldom tolerate just ""\015"". If you get in the habit of using ""\n"" for networking, you may be burned some day.