Update a file with new user input preserving first few lines as a header. Started from LPTHW Example 16

lpthw_ex16_changinglines.py

#http://learnpythonthehardway.org/book/ex16.html
#http://stackoverflow.com/questions/11584247/how-can-i-simplify-this-series-of-target-write-commands
#http://stackoverflow.com/questions/12790983/multiline-file-read-in-python

from sys import argv

script, filename = argv

title_lines = 2

print "We're going to all of %r but the first line." % filename
print "If you don't want that, hit CTRL-C (^C)."
print "If you do want that, hit RETURN."

raw_input("?")

print "Opening the file..."
target = open(filename, 'r+') #can be used only if file exists, a+ if you don't care.

title = [target.readline() for _ in range(title_lines)]


print "Truncating the file after title lines.  Goodbye Garbage!"
target.truncate() #can pass this a character position to start/stop.

print "Now I'm going to ask you for three new lines."

line1 = raw_input("line 1: ")
line2 = raw_input("line 2: ")
line3 = raw_input("line 3: ")

print "I'm going to write these to the file."


target.write('{}\n{}\n{}\n'.format(line1, line2, line3))

#or
#target.write('\n'.join((line1,line2,line3))+'\n')

#or
#lines=(line1,line2,line3)
#target.write( '\n'.join(lines) + '\n')

print "Close the file."
target.close()

print '''Verify write:
--------------------------------------------------'''
target = open(filename, 'r')
print target.read()
print '''--------------------------------------------------
Close File'''
target.close()