The other way around :)

Mac  CR   \015     \x0D     \r
DOS  CRLF \015\012 \x0D\x0A \r\n
*Nix LF   \012     \x0A     \n

(Assuming \r is chr(13) and \n is chr(10), which isn't always true)

The regex to substitute them all would be s/\cM|\cM\cJ|\cJ/$foo/, which can be simplified to s/\cM\cJ?|\cJ/$foo/. But if you don't need to substitute, removing can be done a lot faster by just using tr/\cM\cJ//d (the /d will have tr/// delete characters not found in the replacement pattern (the replacenent pattern is empty in this example)).

2;0 juerd@ouranos:~$ perl -e'undef christmas'
Segmentation fault
2;139 juerd@ouranos:~$
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