text: import sys
  import matplotlib.pyplot as plt
  import numpy as np
  
  def main():
      if len(sys.argv) < 2:
          print("Usage: python3 {} <file1> [file2 ...]".format(sys.argv[0]))
          return 1
      
      # Get carbon and oxygen values
      c12_file = []
      for archiv in sys.argv[1:]:
          c12 = []
          with open(archiv, "r") as fread:
              # Read header
              header = fread.readline().split(",")
              #iC12 = header.index(" C12")
              iC12 = 7
              
              # Now get values
              for line in fread:
                  lnlst = line.split()
                  c12.append(float(lnlst[iC12]))
          
          c12_file.append(c12)
  
      labels = ["3", "4", "5"]
      styles = ["bo-", "g^-", "ys-"]
      for ii in range(len(sys.argv[1:])):
          c12 = c12_file[ii]
          plt.plot(range(1, len(c12) + 1), c12, styles[ii], lw = 2,
                  markersize = 10, label = labels[ii] + " M$_\odot$")
  
      plt.legend(loc = 0, numpoints = 1, prop = {'size': 12})
      plt.ylabel("$^{12}$C mass fraction", size = 14)
      plt.xlabel("TDU number", size = 14)
      plt.tick_params(right = True, top = True)
      
      # Minor ticks
      plt.minorticks_on()
      plt.tick_params(which = "minor", right = True)
      plt.tick_params(which = "minor", bottom = False)
      
      plt.subplots_adjust(hspace = 0)
      
      # Set integer tick labels
      maxim_tick = max(plt.xticks()[0])
      plt.xticks(np.arange(0, maxim_tick, step = 1))
  
      plt.savefig('c12MassFractions.pdf')
      plt.show()
  
  if __name__ == "__main__":
      main()
  