"Command-line Computing" Exercise

Command-line Application

Open the Terminal application (Mac) or the Git Bash application (Windows).

Git Bash (Windows OS)

FYI: Windows users who are into maximum efficiency through keyboard shortcuts can get there quickly by pressing the "windows" button, then begin typing the word "git", then hit enter when you see "Git Bash" show up. 😺

Terminal (Mac OS)

FYI: Mac users who are into maximum efficiency through keyboard shortcuts can get there quickly by pressing the "command + space" buttons to start a spotlight search, then begin typing the word "terminal", then hit enter when you see "Terminal" show up. :smiley_cat:

a screenshot of the terminal

FYI: Mac users who are interested in customizing Terminal app color themes and keyboard shortcuts can reference the professor's Terminal app configuration notes. :smiley_cat:

Instructions

After typing each of the commands below, press "enter" to execute it.

Optionally clear previous terminal output at any time by pressing "command + k", or by typing clear and pressing "enter".

Current User

Display the current user's name:

whoami

Present Working Directory

Display the current/present working directory:

pwd

Listing Files in a Directory

List files in the current working directory:

ls
ls -al # for a different display

Navigating and Managing Directories

Change directories (specifying an absolute file path):

cd ~/Desktop

FYI: the tilde (~) represents your "home" filepath

FYI: you can use cd .. to move "up" one directory relative to the current working directory

Open a directory via the operating system's filesystem explorer:

# Mac Terminal:
open .

# Windows Git Bash:
explorer .

Make a new directory:

mkdir my_folder

Remove a directory:

rm my_folder # triggers an error
rm -rf my_folder # recursively (-r) forces (-f) removal

Managing Files

Setup a new directory in which to add some files, and navigate into that directory:

mkdir my_folder
cd my_folder

Create one or more files in the new directory you just created:

touch README.md
touch index.html
touch my_data.csv
touch my_message.txt

Remove a file:

rm index.html

Edit and save a file, using a command-line utility provided by your preferred text editor (like VS Code):

code my_message.txt # may first require installation of shell commands from the settings

NOTE: Mac users may need to first configure the code command by following these VS Code shell command setup instructions

Display file contents:

cat my_message.txt

Move a file:

mv ~/Desktop/my_folder/my_message.txt ~/Desktop

FYI: If you are into maximum efficiency, press "tab" to auto-complete file paths so you don't have to type the whole thing. :smiley_cat:

Copy a file:

cp ~/Desktop/my_message.txt ~/Desktop/my_folder

Copy contents of a file into the clipboard for pasting:

# Mac OS:
pbcopy < ~/Desktop/my_folder/my_message.txt

# Windows OS:
cat ~/Desktop/my_folder/my_message.txt | clip

# ... then just paste as you normally would after copying some text

Further Exploration (Mac only)

There are many other utilities to use from the command-line.

First, turn up the volume on your computer so everyone around you can hear, then make it speak:

say "Hello, I am your computer. Let's be friends." # or something else polite and appropriate

Optionally explore additional command-line interfaces, if you're curious.

Internet Computing

Trace the route traveled by a network request:

traceroute google.com
# ... stop after a few seconds if necessary by pressing: control + c

Time the duration of a network request:

ping google.com
# ... stop after a few seconds if necessary by pressing: control + c

Request the contents of a webpage:

curl google.com
curl http://www.google.com
curl https://raw.githubusercontent.com/prof-rossetti/intro-to-python/master/data/products.json