Exercise 09-04:
Create a program that takes the names of two files as command line parameters and generates an output file with the lines from the first followed by the lines from the second file. The name of the output file can also be passed as a parameter on the command line.
Answer:
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# Python From Scratch
# Author: Nilo Ney Coutinho Menezes
# Editora Novatec (c) 2010-2025 - LogiKraft 2025
# Site: https://pythonfromscratch.com
# ISBN: 978-85-7522-949-1 (Paperback), 978-85-7522-950-7 (hardcover), 978-85-7522-951-4 (ebook)
#
# File: chapter 09/exercise-09-04.py.py
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import sys
# Check if parameters were passed
if len(sys.argv) != 4: # Remember that the program name is the first in the list
print("\nUsage: e09-04.py first second output\n\n")
else:
first = open(sys.argv[1], "r")
second = open(sys.argv[2], "r")
output = open(sys.argv[3], "w")
# Works similar to readlines
for l1 in first:
output.write(l1)
for l2 in second:
output.write(l2)
first.close()
second.close()
output.close()