#!/usr/bin/env perl
use strict;
use warnings;

my @args = @ARGV;
my %opt;

$opt{f} = '%g';

foreach (@args) {
    if ($_ =~ /^-(\D)$/) {
        shift @args;
        $opt{$1} = shift @args;
    }
    else {
        last;
    }
}

my ($first, $increment, $last) = (1, 1, 1);
if (scalar @args == 1) {
    $last = $args[0];
}
elsif (scalar @args == 2) {
    $first = $args[0];
    $last  = $args[1];
}
elsif (scalar @args == 3) {
    $first     = $args[0];
    $increment = $args[1];
    $last      = $args[2];
}
else {
    die 'invalid argument(s)';
}

for (
    my $i = $first;
    ($increment > 0) ? $i <= $last : $i >= $last;
    $i += $increment
    )
{
    printf "$opt{f}\n", $i;
}