public/subjects/devops/skip_secrets/README.md

skip_secrets

Instructions

You need to write a script, skip_secrets.py, that will be able to decrypt the text coming form a specific file.

The script will receive a file name as the first argument, check if the file is readable, filter the content by skipping all the lines containing pineapple and save the result in a file out.txt

If the file passed as argument is not readable or the number of arguments is not the one expected, the script should exit with a status code 1.

Usage

Below an example of how the script is supposed to work:

$ cat -e file.txt
A normal pizza $
Another normal pizza$
A pizza with pineapple$
Yet another very normal and delicious pizza$
$ python3 skip_secrets.py
$ echo $?
1
$ python3 skip_secrets.py file.txt
$ cat out.txt
A normal pizza $
Another normal pizza$
A pizza with pineapple$
Yet another very normal and delicious pizza$
$

Hints

• It is possible to read arguments passed to a python script using the sys module. Here is an example of script (argv.py):

import sys

for argv in sys.argv:
    print(argv)

And its output:

$ python3 argv.py 1 2 3 something else
argv.py
1
2
3
something
else
$

• It is possible to interrupt the execution of a script and returning a status code different from 0 with the function exit(). For example, consider the following example.py:

exit(1)

This would be the result:

$ python3 example.py
$ echo $?  # check the status code
1

Reference

Python sys.argv