Try this:

$ perl -e 'print "\lTook \LNow Is The Time\E For All Good Men\n";'
took now is the time For All Good Men
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Update: I finally found that reference table. It's in perlop. Quick recap:

The following escape sequences are available in constructs that 
interpolate and in transliterations.

 \t          tab             (HT, TAB)
 \n          newline         (NL)
 \r          return          (CR)
 \f          form feed       (FF)

<<<snip snip snip>>>

The following escape sequences are available in constructs that 
interpolate but not in transliterations.

           \l          lowercase next char
           \u          uppercase next char
           \L          lowercase till \E
           \U          uppercase till \E
           \E          end case modification
           \Q          quote non-word characters till \E

If "use locale" is in effect, the case map used by "\l", "\L", 
"\u" and "\U" is taken from the current locale.

<<<snip snip snip>>>
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