my %paths = (
    LOG => '/path/to/log.txt',
    ERROR => '/path/to/errorlog.txt',
    INFO => '/path/to/info.txt',
);
my %fh; # key: token, value: filehandle

...
if (...) {
    $text = ...
    append('LOG',$text);
} else {
    ...
}

sub append {
   my ($token, $text) = @_;
   my$ fh
   unless (exists $fh{$token} ) {
       open my $fh, '>>', $paths{$token} or die $!;
       $fh{$token} = $fh;
   }
   print {$fh{$token}} $text;
}