Question

Answer the following questions using linux

1) Write a Python script so that a file whoComesForDinner.txt formatted like this:     

Tuesday we have Joe McHungry and Paul McHungry

Wednesday we have Cindy Johnston and Paul Paulsen Thursday we have Amin Mirzaei and Atefeh Mirzaei gets turned into that:

The McHungry on Tuesday

Cindy and Paul on Wednesday

The Mirzaei on Thursday

2)Write a script that takes as argument a port number. It returns the next port that is not assigned

to anything. To know if a port is assigned, the file /etc/services contains a list of assigned ports, one per line. Here is an example of 3 lines in that file:       

ftp           21/udp http         80/tcp

http-alt 8080/tcp

Here are two examples of how the script should answer:

./nextFreePort.sh 80

82

./nextFreePort.sh 10024

10024

Answer 1

Part 1:

import os
import sys

if not os.path.isfile("whoComesForDinner.txt"):
    print "\nFile not found."
    sys.exit(1)

inputfile = open("whoComesForDinner.txt", "r")
for line in inputfile.readlines(): #Reading line by line
    line = line.rstrip('\n') #Removing new lines.
    words = line.split(' ') #Splitting into words.
    if words[4].lower() == words[7].lower(): #If surnames are same.
        sentence = "The " + words[7] + " on " + words[0]
    else:
        sentence = words[3] + " and " + words[6] + " on " + words[0]
    print "\n", sentence
inputfile.close()

Output:

sh-4.3$ python main.py The McHungry on Tuesdav Cindy and Paul on Wednesday The Mirzaei on Thursdav

Part 2:

import os

import sys

if not os.path.isfile("/etc/services"):
    print "\nFile services not found."
    sys.exit(1)

ports = [] #To store busy ports
port = int(raw_input("\nEnter port no.: "))
inputfile = open("/etc/services", "r")
for line in inputfile.readlines():
    line = line.rstrip('\n')
    words = line.split(' ')
    for word in words:
        if word.split('/')[0].isdigit(): #if word contains port number.
            ports.append(int(word.split('/')[0])) #insert port no. into ports.
ports.sort() #Sorting ports
for i in range(port, (ports[len(ports) - 1] + 1)): #From port to all other large nos.
    if i not in ports: #if port is not busy.
        print "Next available port: ", i
        break
inputfile.close()

Output:

Enter port no.: 22 Next available port: 26 sh-4.3