foreach my $entry ( split( /;/, $file_data ) ) {
  do { s/^\s+//; s/\s+$//; } for $entry;
  push @email_list, $entry;
}

##</code><code>##

print join( "\n", sort map { (my $t=$_)=~s/^\s+//;$t=~s/\s+$//;$t } split( /;/, $file_data ) ), "\n";

##</code><code>##

my @email_list = sort map ... split( /;/, $file_data );
print join( "\n", @email_list ), "\n";