Normalizing line endings in Ruby

ruby newline line-breaks
Peter picture Peter · Dec 2, 2009 · Viewed 12.5k times · Source

I have a string in Ruby, s (say) which might have any of the standard line endings (\n, \r\n, \r). I want to convert all of those to \ns. What's the best way?

This seems like a super-common problem, but there's not much documentation about it. Obviously there are easy crude solutions, but is there anything built in to handle this?

Elegant, idiomatic-Ruby solutions are best.

EDIT: realized that ^M and \r are the same. But there are still three cases. (See wikipedia.)

Answer

Greg picture Greg · Jan 8, 2014

Since ruby 1.9 you can use String::encode with universal_newline: true to get all of your new lines into \n while keeping your encoding unchanged:

s.encode(s.encoding, universal_newline: true)

Once in a known newline state you can freely convert back to CRLF using :crlf_newline. eg: to convert a file of unknown (possibly mixed) ending to CRLF (for example), read it in binary mode, then :

s.encode(s.encoding, universal_newline: true).encode(s.encoding, crlf_newline: true)

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