Development with a
Command Line
Copyright © 2022 by Robert Collier. All Rights Reserved.
Learning Outcomes
by the End of this Lecture, Attendees that Complete
the Recommended Exercises should be Able to:
Summarize the Program Development Cycle
Describe the Command Line and File Structure
Copyright © 2022 by Robert Collier. All Rights Reserved.
2
Mandatory Reading Assignment
No Reading Assignment
Copyright © 2022 by Robert Collier. All Rights Reserved.
3
Reintroduction to Computers
Computers are Not Inherently Intelligent devices
but they do Follow Instructions Precisely
they are Useful for Solving Problems Only If a
Programmer has Implemented a Suitable Algorithm
Copyright © 2022 by Robert Collier. All Rights Reserved.
4
Reintroduction to Computers
A Computer...
...is an Electronic Device...
...for Storing and Processing Data...
...by Following Instructions...
...provided in a Computer Program.
Copyright © 2022 by Robert Collier. All Rights Reserved.
5
Highlights from History
because of his Design for the Entirely
Mechanical "Analytical Engine"
Charles Babbage (1791 – 1871) is
known as the Father of the Computer
the Analytical Engine would Only have had about
16.7 kB of Memory, but it was Never Actually Built
Copyright © 2022 by Robert Collier. All Rights Reserved.
6
Highlights from History
Ada Lovelace (1815-1852) was a
Mathematician and Writer, and is
Recognized as having been the
First Programmer
she wrote a Program for Bernouilli Number Sequence
values for the (Nonexistant) Analytical Engine
Copyright © 2022 by Robert Collier. All Rights Reserved.
7
Introduction to Programming
it is Extremely Difficult to Design Algorithms in
Anything Other than Natural Language
in most cases, you Do Not Need and Should Not Use a
Computer to Design an Algorithm
Copyright © 2022 by Robert Collier. All Rights Reserved.
8
Introduction to Programming
when facing a New Problem that you intend to
Solve by Creating a Computer Program...
1. Use Natural Language to Determine How to Solve it
2. Use Pseudocode or Flowcharts to Design the Algorithm
3. Translate the Algorithm with a Programming Language
Copyright © 2022 by Robert Collier. All Rights Reserved.
9
Development Cycle
the Development Cycle is the Sequence of
Activities that should be Followed during the
Creation (and Subsequent Evolution) of a Solution
for this Introductory Course, we are Less Concerned
with the Evolution of a Program and, as a result, can
Regard the Cycle as a Linear Sequence
Copyright © 2022 by Robert Collier. All Rights Reserved.
10
Development Cycle
1
5
Analysis
Maintenance
2
Design
4
Testing
3
Implementation
Copyright © 2022 by Robert Collier. All Rights Reserved.
11
Using a Terminal or Command Prompt
the Development Cycle used in this class Requires
a Terminal or Command Prompt (for Testing)
a Command Prompt is an Entry Point,
Allowing the User to Perform Tasks without using
a Graphical User Interface
Copyright © 2022 by Robert Collier. All Rights Reserved.
12
Using a Terminal or Command Prompt
Operating Systems use Hierarchical File Systems
Any Process will be "looking" at only a single Folder
(i.e., the Working Directory) at any one time
known as the "Root" directory
/
home
student
desktop
the Working Directory when
you first start the Terminal in
a Virtual Linux Environment
documents
Copyright © 2022 by Robert Collier. All Rights Reserved.
13
Using the Windows Command Prompt
typing "dir" in the Command Prompt will List
the Contents of the Current Working Directory
typing "cd" (and nothing else) in the Command Prompt
will Display the Path to the Current Working Directory
typing "cd" followed by the Path to Another Directory,
will Change the Working Directory (n.b., the path ".."
can be used to refer to the Directory directly Above the
Working Directory in the Hierarchy)
Copyright © 2022 by Robert Collier. All Rights Reserved.
14
Using the Linux Terminal
typing "ls" in the Terminal will List
the Contents of the Current Working Directory
typing "pwd" in the Terminal will Display the Path
to the Current Working Directory
typing "cd" followed by the Path to Another Directory,
will Change the Working Directory (n.b., the path ".."
can be used to refer to the Directory directly Above the
Working Directory in the Hierarchy)
Copyright © 2022 by Robert Collier. All Rights Reserved.
15
Python from a Command Prompt
typing "python" (or sometimes the alias "python3")
in will Activate Interactive Mode, allowing you to
Run Python Statements One-At-A-Time
typing "python" (or "python3") Followed by a Filename
will Run Python in Normal Mode, Executing All of the
Statements in the Program contained in that File
Copyright © 2022 by Robert Collier. All Rights Reserved.
16
Learning Outcomes
by the End of this Lecture, Attendees that Complete
the Recommended Exercises should be Able to:
Summarize the Program Development Cycle
Describe the Command Line and File Structure
Copyright © 2022 by Robert Collier. All Rights Reserved.
17