gistfile1.pl

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

# OS X doesn't have seq.  Quick implementation with no
# error checking, and only supports the requirements for
# for i in `seq <low> <high> ; do <command> ; done

my ( $first, $last ) = @ARGV;

print $_ == $last ? "$_\n" : "$_ " for ( $first .. $last );

perl -E 'say join q{ }, $ARGV[0] .. $ARGV[1]' 10 20
10 11 12 13 14 15 16 17 18 19 20