However, your code will stop working if you consider

my $string = "--This is a comment\nNot a comment\n" .
    "--This Comment continues here\nNOT a comment";
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Comments do not necessarily occur at the beginning of the (rest of the) string. (At least that's how I understood the question.) I propose to simply do

my $string = "...";

$string =~ s/(^|\n)--[^\n]+//g;

print "No comments: $string\n";
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If you're perfectionistic, you will notice that this will leave a leading newline if the string starts with a comment. You can fix that by using

my $string = "...";

$string =~ s/\n--[^\n]+//g;
$string =~ s/^--[^\n]+\n//;

print "No comments: $string\n";
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