gw1:~ # perl -nle '
> BEGIN{
> $input_file = shift;
> $required_fields = shift
> }
> my ($field,$val) = split/:/;
> next unless defined $field; #Skip lines with no field names
> $fields{$field} = $val;
> END{
> print join ',' @fields{split/,/,$required_fields}
> }' your_file 'email,fullName,gui'
No comma allowed after filehandle at -e line 10.