perl and sustitution

I have file:

return Math.round(num * Math.pow(10, dec)) / Math.pow(10, dec); 
$ld_div_asig = round(($ld_assigned/4),2);
$ld_rest=round(($ld_assigned-$ld_total),3);
$ld_div_asig = round(($ld_assigned/12),4);
$ld_div_asig = round(($ld_assigned/4),3);
$ld_rest1=round(($ld_assigned-$ld_total),3);
$ldec_total_balance=round($ldec_total_debit-$ldec_total_credit,3);
$ldec_debit=round($this->ds_Prebalance->getValue("total_debit",$li_z),2);
$ldec_credit=round($this->ds_Prebalance->getValue("total_credit",$li_z),2);
$ld_total_debit=round($rs_data->fields["total_debit"],2);

I want to change all round numeric aproximation to 4, so my expect is:

return Math.round(num * Math.pow(10, dec)) / Math.pow(10, dec); 
$ld_div_asig = round(($ld_assigned/4),4);
$ld_rest=round(($ld_assigned-$ld_total),4);
$ld_div_asig = round(($ld_assigned/12),4);
$ld_div_asig = round(($ld_assigned/4),4);
$ld_rest1=round(($ld_assigned-$ld_total),4);
$ldec_total_balance=round($ldec_total_debit-$ldec_total_credit,4);
$ldec_debit=round($this->ds_Prebalance->getValue("total_debit",$li_z),4);
$ldec_credit=round($this->ds_Prebalance->getValue("total_credit",$li_z),4);
$ld_total_debit=round($rs_data->fields["total_debit"],4);

if I try perl -pe 's/(round\((.*?),)([0-9])/$14/g' file
it gives me:

return Math.round(num * Math.pow(10, dec)) / Math.pow(10, dec); 
$ld_div_asig = );
$ld_rest=);
$ld_div_asig = );
$ld_div_asig = );
$ld_rest1=);
$ldec_total_balance=);
$ldec_debit=);
$ldec_credit=);
$ld_total_debit=);

But if add space at the sustitution part, perl -pe 's/(round\((.*?),)([0-9])/$1 4/g' file
it gives me:

return Math.round(num * Math.pow(10, dec)) / Math.pow(10, dec); 
$ld_div_asig = round(($ld_assigned/4), 4);
$ld_rest=round(($ld_assigned-$ld_total), 4);
$ld_div_asig = round(($ld_assigned/12), 4);
$ld_div_asig = round(($ld_assigned/4), 4);
$ld_rest1=round(($ld_assigned-$ld_total), 4);
$ldec_total_balance=round($ldec_total_debit-$ldec_total_credit, 4);
$ldec_debit=round($this->ds_Prebalance->getValue("total_debit",$li_z), 4);
$ldec_credit=round($this->ds_Prebalance->getValue("total_credit",$li_z), 4);
$ld_total_debit=round($rs_data->fields["total_debit"], 4);

It’s what I want but I’d like to get it without the aditional space between the , and the 4.

Is there a way to do the sustitution in perl or sed without adding the aditional space?

>Solution :

You could also write your one-liner as perl -pe 's/(round\((.*?),)([0-9])/${1}4/g' file — that is, write ${1} instead of $1. As you wrote it, Perl reads $14 as referring to capture group 14.