#3-8

 "makeTextFile.py -- create text file"

 import os

 ls = os.linesep

 #get filename

 fname = raw_input()

 while True:

   if os.path.exists(fname):

     print "ERROR: '%s' already exists" % fname

   else:

     break

 all = []

 print "\nEnter lines ('.' by itself to quit).\n"      

 while True:

   entry = raw_input('newline:')

   if entry == '.':

     break

   else:

     all.append(entry)

 fobj = open(fname, 'w')

 fobj.writelines(['%s%s' % (x, ls) for x in all])

 fobj.close()

 print "DONE!" 

 #3-10

 "readtextFile.py---read and display text"

 import os

 fname = raw_input("Enter file name:")

 print

 if os.path.exists(fname):

   fobj = open(fname, 'r')

   for eachline in fobj:

     print eachline.strip()

   fobj.close()

 else:

   print "file not exists!!"  

 #3-11

 "readtextFile.py---read and display text"

 fname = raw_input("Enter file name:")

 print

 try:

   fobj = open(fname, 'r')

 except IOError, e:

   print "*** file open error: ", e

 else:

   for eachline in fobj:

     print eachline.strip()

   fobj.close()  

 #3-12

 "readtextFile.py---read and display text"

 import os

 ls = os.linesep

 print """Enter your option:

 (w)create a file

 (r)read a file

 (others)exit

 """

 def WriteFile(str):

   all = []

   if os.path.exists(str):

     print "ERROR: '%s' already exists" % fname

     return

   print "\nEnter lines ('.' by itself to quit).\n"

   while True:

       entry = raw_input('newline:')

       if entry == '.':

         break

       else:

         all.append(entry)

     fobj = open(fname, 'w')

     fobj.writelines(['%s%s' % (x, ls) for x in all])

     fobj.close()

     print "DONE!" 

 def ReadFile(str):

   #fname = raw_input("Enter file name:")

   print

   if os.path.exists(str):

       fobj = open(str, 'r')

       for eachline in fobj:

         print eachline.strip()

       fobj.close()

   else:

       print "file not exists!!" 

 opt =raw_input("your option is:")

 if(opt == 'w'):

   fname = raw_input("the file to write is: ")

   WriteFile(fname)

 elif opt== 'r':

   fname = raw_input("the file to read is: ")

   ReadFile(fname)

 else:

   print "exit" 

 #3-13

 "readtextFile.py---read and display text"

 import os

 ls = os.linesep

 print """Enter your option:

 (w)create a file

 (r)read a file

 (m)modify a file

 (others)exit

 """

 def WriteFile(str):

   all = []

   if os.path.exists(str):

     print "ERROR: '%s' already exists" % fname

     return

   print "\nEnter lines ('.' by itself to quit).\n"

   while True:

       entry = raw_input('newline:')

       if entry == '.':

         break

       else:

         all.append(entry)

     fobj = open(fname, 'w')

     fobj.writelines(['%s%s' % (x, ls) for x in all])

     fobj.close()

     print "DONE!" 

 def ReadFile(str):

   #fname = raw_input("Enter file name:")

   print

   if os.path.exists(str):

       fobj = open(str, 'r')

       for eachline in fobj:

         print eachline.strip()

       fobj.close()

   else:

       print "file not exists!!" 

 def ModifyFile(str):

   all = []

   if os.path.exists(str):

     i = 1

     fobj = open(str, 'r')

     for eachline in fobj:

       newline = eachline.strip()

       print "line %d: %s" % (i,newline)

       newline = raw_input("replace with:")

       all.append(newline)

       i+=1

     fobj.close()

     opt = raw_input("do you want to save your changes,\ny(yes) \nother(n):")

     if opt == 'y':

       output = open(str, 'w')

       output.writelines(['%s%s' % (x, ls) for x in all])

       output.close()

     else:

       return

   else:

     print "file not exists!!"       

 opt =raw_input("your option is:")

 if(opt == 'w'):

   fname = raw_input("the file to write is: ")

   WriteFile(fname)

 elif opt== 'r':

   fname = raw_input("the file to read is: ")

   ReadFile(fname)

 elif opt == 'm':

   fname = raw_input("the file to modify is:")

   ModifyFile(fname)

   print "the new file content is:"

   ReadFile(fname)

 else:

   print "exit"