Sure. Sorry I didn't put an explanation in the first post.

First, you are trying to get around the problem that you can't use s/// on a constant value (literal string "April 1, 2009"), so my first thought was this two-liner:

my $chosen_day = "April  1, 2009";
$chosen_day =~ s/\s\s/ /;
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In case you haven't seen it, the =~ operator binds the string on the left to the pattern on the right (see perlop). But you asked for a one-liner, so I took advantage of the fact that the return value of an assignment can be bound to a pattern as well:

# Parenthesized assignment is bound to the substitution
(my $c = "April  1, 2009") =~          s/\s\s/ /;
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