content: #!/usr/bin/env python2
  """
  Author        :Julio Sanz
  Website       :www.elarraydejota.com
  Email         :juliojosesb@gmail.com
  Description   :Script to create a graph about swap usage
  Dependencies  :Python 2.x, matplotlib
  Usage         :python swap.py
  License       :GPLv3
  """
  
  import matplotlib
  matplotlib.use('Agg')
  import matplotlib.pyplot as plt 
  import csv
  from datetime import datetime
  import matplotlib.dates
  
  # ======================
  # VARIABLES
  # ======================
  
  # Aesthetic parameters
  plt.rcParams.update({'font.size': 8})
  plt.rcParams['lines.linewidth'] = 1.5
  time_format = matplotlib.dates.DateFormatter('%H:%M:%S')
  plt.gca().xaxis.set_major_formatter(time_format)
  plt.gcf().autofmt_xdate()
  
  # Time (column 0)
  x = []
  # Data arrays
  swap_free = []
  swap_used = []
  
  # ======================
  # FUNCTIONS
  # ======================
  
  def generate_graph():
      with open('../../data/swap.dat', 'r') as csvfile:
          data_source = csv.reader(csvfile, delimiter=' ', skipinitialspace=True)
          for row in data_source:
              # [0] column is a time column
              # Convert to datetime data type
              a = datetime.strptime((row[0]),'%H:%M:%S')
              x.append((a))
              # The remaining columns contain data
              swap_free.append(str(int(row[1])/1024))
              swap_used.append(str(int(row[2])/1024))
              
  
      # Plot lines
      plt.plot(x,swap_used, label='Used', color='r', antialiased=True)
      plt.plot(x,swap_free, label='Free', color='g', antialiased=True)
      
      # Graph properties
      plt.xlabel('Time',fontstyle='italic')
      plt.ylabel('SWAP (MB)',fontstyle='italic')
      plt.title('SWAP usage graph')
      plt.grid(linewidth=0.4, antialiased=True)
      plt.legend(loc='upper center', bbox_to_anchor=(0.5, -0.15), ncol=2, fancybox=True, shadow=True)
      plt.autoscale(True)
      
      # Graph saved to PNG file
      plt.savefig('../../graphs/swap.png', bbox_inches='tight')
      #plt.show()
  
  # ======================
  # MAIN
  # ======================
  
  if __name__ == '__main__':
      generate_graph()