Shell Programming and Scripting

while(<>)
{
  chomp;
  @a= split(/,/);
  $sum{$a[0]} += $a[1];
}

foreach $key (keys %sum)
{
  print "$key,$sum{$key}\n";
}

awk 'BEGIN{FS=","}
{ array[$1]+=$2 }
END{
for (i in array) print i,array[i] 
}' "file"

while(<>)
{
  chomp;
  @a= split(/,/);
  push (@order,$a[0]) if (!$sum{$a[0]});
  $sum{$a[0]} += $a[1];
}

foreach $key (@order)
{
  print "$key,$sum{$key}\n";
}