File Manipulation with Python

Scenarios are quite common where an IT professional is tasked with modify a file on many computer systems or many files on a single computer or a combination of the two. For example, a large software may need the copyright notice comment to be changed on every source file in the project. Or, a configuration file may need to be modified on every server in a multi-server deployment. Doing this task manually is not a viable way to approach the problem. Instead, a better solution is to use a scriptable environment to perform search and replace functionality on the files in question. Python is an excellent tool for this kind of task.

Description

Samba is a unix/linux file sharing suite of programs designed to provide Windows interoperable file and print sharing services. Much of the configuration for the Samba daemon is provided by the text file smb.conf (renamed to smb.txt for this assignment). After an update was deployed to three dozen linux servers it was discovered that a couple of configured parameters were incorrect. Unfortunately, since there are unique aspects to each server, copying the contents of a single file to each server is not a viable solution. To fix the problem, the IT department must connect to each server, edit the smb.conf file, and restart the smbd daemon. To automate this task, each server will have a Python script copied to it. Then an SSH session will be initiated to each server from which the script will be executed. Your task is to write the Python script.

The invocation of the script must be as follows:

python modify.py fileSpec from to

where,

modify.py is the name of your script

fileSpec is the name of the file to be modified (smb.txt)

from is the text to be searched for (be sure to enclose any white space in quotes.

to is the text the searched text is to be replaced with.

Testing the script is your responsibility. However a good test case is:

python modify.py smb.txt password sync = yes password sync = no