#!/usr/bin/perl

$last = $ARGV[-1];
splice(@ARGV, -1);

open(PIPE, "ledger -MG @ARGV register $last |") || die;
@values = ();
while (<PIPE>) {
    ($date, $value) = split;
    push @values, $value;
}
close(PIPE);

@values = sort @values;
splice(@values, 0, 1);
splice(@values, -1);

$value = 0.0;
for $item (@values) {
  $value += $item;
}

if (@values) {
    printf("%.2f\n", $value / @values);
} else {
    die "There are no values to average!\n";
}