The shell of a new line is usually a carriage return, i.e. Character cr or, as mentioned in others, in String cr . If you want to support all standard newline formats, just include both standard delimiters, for example:
string := 'smalltalk is a lot of fun.'. string findTokens: String cr, String lf.
Since you are now mentioning that you are using VisualWorks, the above will not work unless you have the squeak-accessing category loaded (which probably won't if you are not using Seaside). Instead, you can use a regex:
'foo bar' allRegexMatches: '[^', (String with: Character cr), ']+'
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