#!/usr/bin/ruby -w
# Remove leading or trailing lines.
#
#  argument >= 0  -> drop leading lines.
#  argument < 0   -> drop trailing lines.

if ARGV.size == 0
   print "#{$0} {line_count}\n"
   exit 1
end

count = ARGV.shift.to_i
if count >= 0
   ARGF.each_line.drop(count).each{print it}
else
   buffer = []
   ARGF.each_line{
      buffer += [it]
      if buffer.size > -count
         print buffer.shift
      end
   }
end