Linux Shell and Bash Hacks • 49 min read

(base) parav@Paravs-MacBook-Air ~ % %%script bash
fg: no current job
(base) parav@Paravs-MacBook-Air ~ % cat <<EOF > /tmp/variables.sh
heredoc> export project_dir=$HOME/vscode 
heredoc> export project=\$project_dir/teacher
heredoc> export project_repo="https://github.com/nighthawkcoders/teacher.git"
heredoc> EOF
(base) parav@Paravs-MacBook-Air ~ % source /tmp/variables.sh
(base) parav@Paravs-MacBook-Air ~ % echo "Project dir: $project_dir"
Project dir: /Users/parav/vscode
(base) parav@Paravs-MacBook-Air ~ % echo "Project: $project"
Project: /Users/parav/vscode/teacher
(base) parav@Paravs-MacBook-Air ~ % echo "Repo: $project_repo"
Repo: https://github.com/nighthawkcoders/teacher.git
(base) parav@Paravs-MacBook-Air ~ % source /tmp/variables.sh
(base) parav@Paravs-MacBook-Air ~ % echo "Using conditional statement to create a project directory and project"
Using conditional statement to create a project directory and project
(base) parav@Paravs-MacBook-Air ~ % cd ~
(base) parav@Paravs-MacBook-Air ~ % if [ ! -d $project_dir ]
then
    echo "Directory $project_dir does not exists... makinng directory $project_dir"
    mkdir -p $project_dir
fi
echo "Directory $project_dir exists."
Directory /Users/parav/vscode exists.
(base) parav@Paravs-MacBook-Air ~ % if [ ! -d $project ]
then
    echo "Directory $project does not exists... cloning $project_repo"
    cd $project_dir
    git clone $project_repo
    cd ~
fi
echo "Directory $project exists."
Directory /Users/parav/vscode/teacher does not exists... cloning https://github.com/nighthawkcoders/teacher.git
Cloning into 'teacher'...
remote: Enumerating objects: 1924, done.
remote: Counting objects: 100% (492/492), done.
remote: Compressing objects: 100% (192/192), done.
remote: Total 1924 (delta 316), reused 468 (delta 300), pack-reused 1432
Receiving objects: 100% (1924/1924), 8.53 MiB | 13.63 MiB/s, done.
Resolving deltas: 100% (1231/1231), done.
Directory /Users/parav/vscode/teacher exists.
(base) parav@Paravs-MacBook-Air ~ % source /tmp/variables.sh
(base) parav@Paravs-MacBook-Air ~ % echo "Navigate to project, then navigate to area wwhere files were cloned"
cd $project
pwd
Navigate to project, then navigate to area wwhere files were cloned
/Users/parav/vscode/teacher
(base) parav@Paravs-MacBook-Air teacher % echo ""
echo "list top level or root of files with project pulled from github"
ls

list top level or root of files with project pulled from github
Gemfile		_config.yml	_notebooks	csp.md		indexBlogs.md
LICENSE		_data		_posts		csse.md		scripts
Makefile	_includes	assets		images
README.md	_layouts	csa.md		index.md
(base) parav@Paravs-MacBook-Air teacher % source /tmp/variables.sh
(base) parav@Paravs-MacBook-Air teacher % echo "Navigate to project, then navigate to area wwhere files were cloned"
cd $project
pwd
Navigate to project, then navigate to area wwhere files were cloned
/Users/parav/vscode/teacher
(base) parav@Paravs-MacBook-Air teacher % echo ""
echo "list all files in long format"
ls -al 

list all files in long format
total 104
drwxr-xr-x  23 parav  staff   736 Aug 23 12:19 .
drwxr-xr-x  28 parav  staff   896 Aug 23 12:19 ..
drwxr-xr-x  12 parav  staff   384 Aug 23 12:19 .git
drwxr-xr-x   3 parav  staff    96 Aug 23 12:19 .github
-rw-r--r--   1 parav  staff   157 Aug 23 12:19 .gitignore
-rw-r--r--   1 parav  staff   122 Aug 23 12:19 Gemfile
-rw-r--r--   1 parav  staff  1081 Aug 23 12:19 LICENSE
-rw-r--r--   1 parav  staff  3131 Aug 23 12:19 Makefile
-rw-r--r--   1 parav  staff  6853 Aug 23 12:19 README.md
-rw-r--r--   1 parav  staff   607 Aug 23 12:19 _config.yml
drwxr-xr-x   6 parav  staff   192 Aug 23 12:19 _data
drwxr-xr-x  11 parav  staff   352 Aug 23 12:19 _includes
drwxr-xr-x   6 parav  staff   192 Aug 23 12:19 _layouts
drwxr-xr-x  38 parav  staff  1216 Aug 23 12:19 _notebooks
drwxr-xr-x  12 parav  staff   384 Aug 23 12:19 _posts
drwxr-xr-x   4 parav  staff   128 Aug 23 12:19 assets
-rw-r--r--   1 parav  staff    92 Aug 23 12:19 csa.md
-rw-r--r--   1 parav  staff    98 Aug 23 12:19 csp.md
-rw-r--r--   1 parav  staff   108 Aug 23 12:19 csse.md
drwxr-xr-x  34 parav  staff  1088 Aug 23 12:19 images
-rw-r--r--   1 parav  staff  5149 Aug 23 12:19 index.md
-rw-r--r--   1 parav  staff    53 Aug 23 12:19 indexBlogs.md
drwxr-xr-x   8 parav  staff   256 Aug 23 12:19 scripts
(base) parav@Paravs-MacBook-Air teacher % source /tmp/variables.sh
(base) parav@Paravs-MacBook-Air teacher % echo "Look for posts"
Look for posts
(base) parav@Paravs-MacBook-Air teacher % export posts=$project/_posts
(base) parav@Paravs-MacBook-Air teacher % cd $posts
(base) parav@Paravs-MacBook-Air _posts % pwd
/Users/parav/vscode/teacher/_posts
(base) parav@Paravs-MacBook-Air _posts % ls -l
total 176
-rw-r--r--  1 parav  staff   7685 Aug 23 12:19 2023-08-16-Tools_Equipment.md
-rw-r--r--  1 parav  staff   4650 Aug 23 12:19 2023-08-16-pair_programming.md
-rw-r--r--  1 parav  staff   7137 Aug 23 12:19 2023-08-17-markdown-html_fragments.md
-rw-r--r--  1 parav  staff   6659 Aug 23 12:19 2023-08-23-javascript-calculator.md
-rw-r--r--  1 parav  staff  10642 Aug 23 12:19 2023-08-30-agile_methodolgy.md
-rw-r--r--  1 parav  staff   3849 Aug 23 12:19 2023-08-30-javascript-music-api.md
-rw-r--r--  1 parav  staff   5312 Aug 23 12:19 2023-09-06-javascript-motion-mario-oop.md
-rw-r--r--  1 parav  staff   4812 Aug 23 12:19 2023-09-13-java-free_response.md
-rw-r--r--  1 parav  staff  13220 Aug 23 12:19 2023-10-16-java-api-pojo-jpa.md
-rw-r--r--  1 parav  staff   6819 Aug 23 12:19 2023-11-13-jwt-java-spring.md
(base) parav@Paravs-MacBook-Air _posts % source /tmp/variables.sh
(base) parav@Paravs-MacBook-Air _posts % echo "Look for notebooks"
Look for notebooks
(base) parav@Paravs-MacBook-Air _posts % export notebooks=$project/_notebooks
(base) parav@Paravs-MacBook-Air _posts % cd $notebooks
(base) parav@Paravs-MacBook-Air _notebooks % pwd
/Users/parav/vscode/teacher/_notebooks
(base) parav@Paravs-MacBook-Air _notebooks % ls -l
total 1472
-rw-r--r--  1 parav  staff   13014 Aug 23 12:19 2023-08-01-cloud_database.ipynb
-rw-r--r--  1 parav  staff    8992 Aug 23 12:19 2023-08-01-mario_player.ipynb
-rw-r--r--  1 parav  staff   43705 Aug 23 12:19 2023-08-02-cloud-workspace-automation.ipynb
-rw-r--r--  1 parav  staff   22060 Aug 23 12:19 2023-08-03-mario_block.ipynb
-rw-r--r--  1 parav  staff   11791 Aug 23 12:19 2023-08-03-mario_platform.ipynb
-rw-r--r--  1 parav  staff   19450 Aug 23 12:19 2023-08-03-mario_tube.ipynb
-rw-r--r--  1 parav  staff   24387 Aug 23 12:19 2023-08-04-mario_background.ipynb
-rw-r--r--  1 parav  staff    3496 Aug 23 12:19 2023-08-07-mario_lesson.ipynb
-rw-r--r--  1 parav  staff   10110 Aug 23 12:19 2023-08-15-java-hello.ipynb
-rw-r--r--  1 parav  staff   25656 Aug 23 12:19 2023-08-16-github_pages_setup.ipynb
-rw-r--r--  1 parav  staff   16156 Aug 23 12:19 2023-08-16-linux_shell.ipynb
-rw-r--r--  1 parav  staff   11466 Aug 23 12:19 2023-08-16-python_hello.ipynb
-rw-r--r--  1 parav  staff    9425 Aug 23 12:19 2023-08-23-github_pages_anatomy.ipynb
-rw-r--r--  1 parav  staff   22674 Aug 23 12:19 2023-08-23-java-console_games.ipynb
-rw-r--r--  1 parav  staff    9038 Aug 23 12:19 2023-08-23-python_tricks.ipynb
-rw-r--r--  1 parav  staff   10152 Aug 23 12:19 2023-08-30-javascript_top_10.ipynb
-rw-r--r--  1 parav  staff    9689 Aug 23 12:19 2023-08-30-showcase-S1-pair.ipynb
-rw-r--r--  1 parav  staff    7192 Aug 23 12:19 2023-09-05-python-flask-anatomy.ipynb
-rw-r--r--  1 parav  staff   22157 Aug 23 12:19 2023-09-06-AWS-deployment.ipynb
-rw-r--r--  1 parav  staff   14380 Aug 23 12:19 2023-09-06-java-primitives.ipynb
-rw-r--r--  1 parav  staff   11671 Aug 23 12:19 2023-09-06-javascript-input.ipynb
-rw-r--r--  1 parav  staff   13706 Aug 23 12:19 2023-09-12-java_menu_class.ipynb
-rw-r--r--  1 parav  staff    9562 Aug 23 12:19 2023-09-13-java_fibonaccii_class.ipynb
-rw-r--r--  1 parav  staff   44217 Aug 23 12:19 2023-09-13-javascript_output.ipynb
-rw-r--r--  1 parav  staff   43423 Aug 23 12:19 2023-09-13-python-pandas_intro.ipynb
-rw-r--r--  1 parav  staff   11578 Aug 23 12:19 2023-09-20-java-image_2D.ipynb
-rw-r--r--  1 parav  staff   26739 Aug 23 12:19 2023-09-20-javascript_motion_dog.ipynb
-rw-r--r--  1 parav  staff   13599 Aug 23 12:19 2023-10-02-java-spring-anatomy.ipynb
-rw-r--r--  1 parav  staff   12429 Aug 23 12:19 2023-10-09-java-chatgpt.ipynb
-rw-r--r--  1 parav  staff   15632 Aug 23 12:19 2023-10-09-javascript_api.ipynb
-rw-r--r--  1 parav  staff  113091 Aug 23 12:19 2023-10-09-python_machine_learing_fitness.ipynb
-rw-r--r--  1 parav  staff   16271 Aug 23 12:19 2023-11-13-jwt-python-flask.ipynb
-rw-r--r--  1 parav  staff   15951 Aug 23 12:19 2023-11-13-vulnerabilities.ipynb
-rw-r--r--  1 parav  staff   18328 Aug 23 12:19 2023-11-20-jwt-java-spring-challenge.md
-rw-r--r--  1 parav  staff   10745 Aug 23 12:19 2024-01-04-cockpit-setup.ipynb
drwxr-xr-x  3 parav  staff      96 Aug 23 12:19 files
(base) parav@Paravs-MacBook-Air _notebooks % source /tmp/variables.sh
(base) parav@Paravs-MacBook-Air _notebooks % echo "Look for images in notebooks, print working directory, list files"
Look for images in notebooks, print working directory, list files
(base) parav@Paravs-MacBook-Air _notebooks % cd $notebooks/images
cd: no such file or directory: /Users/parav/vscode/teacher/_notebooks/images
(base) parav@Paravs-MacBook-Air _notebooks % pwd
/Users/parav/vscode/teacher/_notebooks
(base) parav@Paravs-MacBook-Air _notebooks % ls -l
total 1472
-rw-r--r--  1 parav  staff   13014 Aug 23 12:19 2023-08-01-cloud_database.ipynb
-rw-r--r--  1 parav  staff    8992 Aug 23 12:19 2023-08-01-mario_player.ipynb
-rw-r--r--  1 parav  staff   43705 Aug 23 12:19 2023-08-02-cloud-workspace-automation.ipynb
-rw-r--r--  1 parav  staff   22060 Aug 23 12:19 2023-08-03-mario_block.ipynb
-rw-r--r--  1 parav  staff   11791 Aug 23 12:19 2023-08-03-mario_platform.ipynb
-rw-r--r--  1 parav  staff   19450 Aug 23 12:19 2023-08-03-mario_tube.ipynb
-rw-r--r--  1 parav  staff   24387 Aug 23 12:19 2023-08-04-mario_background.ipynb
-rw-r--r--  1 parav  staff    3496 Aug 23 12:19 2023-08-07-mario_lesson.ipynb
-rw-r--r--  1 parav  staff   10110 Aug 23 12:19 2023-08-15-java-hello.ipynb
-rw-r--r--  1 parav  staff   25656 Aug 23 12:19 2023-08-16-github_pages_setup.ipynb
-rw-r--r--  1 parav  staff   16156 Aug 23 12:19 2023-08-16-linux_shell.ipynb
-rw-r--r--  1 parav  staff   11466 Aug 23 12:19 2023-08-16-python_hello.ipynb
-rw-r--r--  1 parav  staff    9425 Aug 23 12:19 2023-08-23-github_pages_anatomy.ipynb
-rw-r--r--  1 parav  staff   22674 Aug 23 12:19 2023-08-23-java-console_games.ipynb
-rw-r--r--  1 parav  staff    9038 Aug 23 12:19 2023-08-23-python_tricks.ipynb
-rw-r--r--  1 parav  staff   10152 Aug 23 12:19 2023-08-30-javascript_top_10.ipynb
-rw-r--r--  1 parav  staff    9689 Aug 23 12:19 2023-08-30-showcase-S1-pair.ipynb
-rw-r--r--  1 parav  staff    7192 Aug 23 12:19 2023-09-05-python-flask-anatomy.ipynb
-rw-r--r--  1 parav  staff   22157 Aug 23 12:19 2023-09-06-AWS-deployment.ipynb
-rw-r--r--  1 parav  staff   14380 Aug 23 12:19 2023-09-06-java-primitives.ipynb
-rw-r--r--  1 parav  staff   11671 Aug 23 12:19 2023-09-06-javascript-input.ipynb
-rw-r--r--  1 parav  staff   13706 Aug 23 12:19 2023-09-12-java_menu_class.ipynb
-rw-r--r--  1 parav  staff    9562 Aug 23 12:19 2023-09-13-java_fibonaccii_class.ipynb
-rw-r--r--  1 parav  staff   44217 Aug 23 12:19 2023-09-13-javascript_output.ipynb
-rw-r--r--  1 parav  staff   43423 Aug 23 12:19 2023-09-13-python-pandas_intro.ipynb
-rw-r--r--  1 parav  staff   11578 Aug 23 12:19 2023-09-20-java-image_2D.ipynb
-rw-r--r--  1 parav  staff   26739 Aug 23 12:19 2023-09-20-javascript_motion_dog.ipynb
-rw-r--r--  1 parav  staff   13599 Aug 23 12:19 2023-10-02-java-spring-anatomy.ipynb
-rw-r--r--  1 parav  staff   12429 Aug 23 12:19 2023-10-09-java-chatgpt.ipynb
-rw-r--r--  1 parav  staff   15632 Aug 23 12:19 2023-10-09-javascript_api.ipynb
-rw-r--r--  1 parav  staff  113091 Aug 23 12:19 2023-10-09-python_machine_learing_fitness.ipynb
-rw-r--r--  1 parav  staff   16271 Aug 23 12:19 2023-11-13-jwt-python-flask.ipynb
-rw-r--r--  1 parav  staff   15951 Aug 23 12:19 2023-11-13-vulnerabilities.ipynb
-rw-r--r--  1 parav  staff   18328 Aug 23 12:19 2023-11-20-jwt-java-spring-challenge.md
-rw-r--r--  1 parav  staff   10745 Aug 23 12:19 2024-01-04-cockpit-setup.ipynb
drwxr-xr-x  3 parav  staff      96 Aug 23 12:19 files
(base) parav@Paravs-MacBook-Air _notebooks % source /tmp/variables.sh
(base) parav@Paravs-MacBook-Air _notebooks % echo "Navigate to project, then navigate to area wwhere files were cloned"
Navigate to project, then navigate to area wwhere files were cloned
(base) parav@Paravs-MacBook-Air _notebooks % cd $project
(base) parav@Paravs-MacBook-Air teacher % echo "show the contents of README.md"
show the contents of README.md
(base) parav@Paravs-MacBook-Air teacher % echo ""

(base) parav@Paravs-MacBook-Air teacher % cat README.md
## Teacher Blog site
This site is intended for the development of Teacher content.  This blogging site is built using GitHub Pages [GitHub Pages](https://docs.github.com/en/pages/getting-started-with-github-pages/creating-a-github-pages-site).
- The purpose is to build lessons and distribute across different Computer Science sections (CSSE, CSP, CSA), a pathway that covers 3 years of High School Instruction.
- The primary languages and frameworks that are taught are `JavaScript/HTML/CSS`, `Python/Flask`, `Java/Spring`.  Read below for more details.
- In this course, Teacher content is not exclusively developed by Teachers.  In fact, many Students have been invited to develop and publish content into this repository.  Their names will appear as authors on the content which they aided in producing.
- This site has incorporated ideas and has radically modified scripts from the now deprecated [fastpages](https://github.com/fastai/fastpages) repository.
- This site includes assistance and guideance from ChatGPT, [chat.openai.com](https://chat.openai.com/) 

### Courses and Pathway
The focus of the Del Norte Computer Science three-year pathway is `Full Stack Web Development`.  This focus provides a variety of technologies and exposures.  The intention of the pathway is breadth and exposure.
- `JavaScript` documents are focused on frontend development and for entry class into the Del Norte Computer Science pathway.  JavaScript documents and materials are a prerequisites to Python and Java classes.
- `Python` documents are focused on backend development and requirements for the AP Computer Science Principles exam.
- `Java` documents are focused on backend development and requirements for the AP Computer Sciene A exam.
- `Data Structures` materials embedded into JavaScript, Python, or Java documents are focused on college course articulation.

### Resources and Instruction
The materials, such as this README, as well as `Tools`, `DevOps`, and `Collaboration` resources are integral part of this course and Computer Science in general.  Everything in our environment is part of our learning of Computer Science. 
- `Visual Studio Code` is key the code-build-debug cycle editor used in this course, [VSCode download](https://code.visualstudio.com/).  This is an example of a resource, but inside of it it has features for collaboration.
- `Tech Talks`, aka lectures, are intended to be interactive and utilize `Jupyter Notebooks` and Websites.  This is an example of blending instruction and tools together, which in turn provide additional resources for learning.  For instance, deep knowledge on  GitHub Pages and Notebooks are valuable in understanding principles behind Full Stack Development and Data Science. 

## GitHub Pages
All `GitHub Pages` websites are managed on GitHub infrastructure. GitHub uses `Jekyll` to tranform your content into static websites and blogs. Each time we change files in GitHub it initiates a GitHub Action that rebuilds and publishes the site with Jekyll.  
- GitHub Pages is powered by: [Jekyll](https://jekyllrb.com/).
- Publised teacher website: [nighthawkcoders.github.io/teacher](https://nighthawkcoders.github.io/teacher/)

## Preparing a Preview Site 
In all development, it is recommended to test your code before deployment.  The GitHub Pages development process is optimized by testing your development on your local machine, prior to files on GitHub

Development Cycle. For GitHub pages, the tooling described below will create a development cycle  `make-code-save-preview`.  In the development cycle, it is a requirement to preview work locally, prior to doing a VSCode `commit` to git.

Deployment Cycle.  In the deplopyment cycle, `sync-github-action-review`, it is a requirement to complete the development cycle prior to doing a VSCode `sync`.  The sync triggers github repository update.  The action starts the jekyll build to publish the website.  Any step can have errors and will require you to do a review.

### WSL and/or Ubuntu installation requirements
- The result of these step is Ubuntu tools to run preview server.  These procedures were created using [jekyllrb.com](https://jekyllrb.com/docs/installation/ubuntu/)
```bash
# 
# WSL/Ubuntu setup
#
mkdir mkdir vscode
git clone https://github.com/nighthawkcoders/teacher.git
# run script, path vscode/teacher are baked in script
~/vscode/teacher/scripts/activate_ubuntu.sh
#=== !!!Start a new Terminal!!! ===
#=== Continue to next section ===

### MacOs installation requirements 
- Ihe result of these step are MacOS tools to run preview server.  These procedures were created using [jekyllrb.com](https://jekyllrb.com/docs/installation/macos/). 

```bash
# 
# MacOS setup
#
mkdir mkdir vscode
git clone https://github.com/nighthawkcoders/teacher.git
# run script, path vscode/teacher are baked in script
~/vscode/teacher/scripts/activate_macos.sh
#=== !!!Start a new Terminal!!! ===
#=== Continue to next section ===


### Run Preview Server
- The result of these step is server running on: http://0.0.0.0:4100/teacher/.  Regeneration messages will run in terminal on any save and update site upon refresh.  Terminal is active, press the Enter or Return key in the terminal at any time to see prompt to enter commands.

- Complete installation
```bash
cd ~/vscode/teacher
bundle install
make

- Run Server.  This requires running terminal commands `make`, `make stop`, `make clean`, or `make convert` to manage the running server.  Logging of details will appear in terminal.   A `Makefile` has been created in project to support commands and start processes.

    - Start preview server in terminal
    ```bash
    cd ~/vscode/teacher  # my project location, adapt as necessary
    make
    ```

    - Terminal output of shows server address. Cmd or Ctl click http location to open preview server in browser. Example Server address message... 
    ```
    Server address: http://0.0.0.0:4100/teacher/
    ```

    - Save on ipynb or md activiates "regeneration". Refresh browser to see updates. Example terminal message...
    ```
    Regenerating: 1 file(s) changed at 2023-07-31 06:54:32
        _notebooks/2024-01-04-cockpit-setup.ipynb
    ```

    - Terminal message are generated from background processes.  Click return or enter to obtain prompt and use terminal as needed for other tasks.  Alway return to root of project `cd ~/vscode/teacher` for all "make" actions. 
        

    - Stop preview server, but leave constructed files in project for your review.
    ```bash
    make stop
    ```

    - Stop server and "clean" constructed files, best choice when renaming files to eliminate potential duplicates in constructed files.
    ```bash
    make clean
    ```

    - Test notebook conversions, best choice to see if IPYNB conversion is acting up.
    ```bash
    make convert
    ```
    %                                                                           (base) parav@Paravs-MacBook-Air teacher % echo ""

(base) parav@Paravs-MacBook-Air teacher % echo "end of README.md"
end of README.md
(base) parav@Paravs-MacBook-Air teacher % echo "Show the shell environment variables, key on left of equal value on right"
Show the shell environment variables, key on left of equal value on right
(base) parav@Paravs-MacBook-Air teacher % env
__CFBundleIdentifier=com.apple.Terminal
TMPDIR=/var/folders/cw/l3n5900n2bl_cmrpnv4h2r500000gp/T/
XPC_FLAGS=0x0
TERM=xterm-256color
SSH_AUTH_SOCK=/private/tmp/com.apple.launchd.GkYDhYHfST/Listeners
XPC_SERVICE_NAME=0
TERM_PROGRAM=Apple_Terminal
TERM_PROGRAM_VERSION=447
TERM_SESSION_ID=693D2B45-A31C-4BD0-8E76-6752A217A1B2
SHELL=/bin/zsh
HOME=/Users/parav
LOGNAME=parav
USER=parav
PATH=/Users/parav/.gem/ruby/2.7.7/bin:/Users/parav/.rubies/ruby-2.7.7/lib/ruby/gems/2.7.0/bin:/Users/parav/.rubies/ruby-2.7.7/bin:/opt/homebrew/opt/openjdk/bin:/Users/parav/opt/anaconda3/bin:/Users/parav/opt/anaconda3/condabin:/Library/Frameworks/Python.framework/Versions/3.11/bin:/opt/homebrew/bin:/opt/homebrew/sbin:/Library/Frameworks/Python.framework/Versions/2.7/bin:/usr/local/bin:/System/Cryptexes/App/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin
SHLVL=1
PWD=/Users/parav/vscode/teacher
OLDPWD=/Users/parav/vscode/teacher/_notebooks
HOMEBREW_PREFIX=/opt/homebrew
HOMEBREW_CELLAR=/opt/homebrew/Cellar
HOMEBREW_REPOSITORY=/opt/homebrew
MANPATH=/opt/homebrew/share/man::
INFOPATH=/opt/homebrew/share/info:
CONDA_EXE=/Users/parav/opt/anaconda3/bin/conda
_CE_M=
_CE_CONDA=
CONDA_PYTHON_EXE=/Users/parav/opt/anaconda3/bin/python
CONDA_SHLVL=1
CONDA_PREFIX=/Users/parav/opt/anaconda3
CONDA_DEFAULT_ENV=base
CONDA_PROMPT_MODIFIER=(base) 
RUBY_ROOT=/Users/parav/.rubies/ruby-2.7.7
RUBYOPT=
RUBY_ENGINE=ruby
RUBY_VERSION=2.7.7
GEM_ROOT=/Users/parav/.rubies/ruby-2.7.7/lib/ruby/gems/2.7.0
GEM_HOME=/Users/parav/.gem/ruby/2.7.7
GEM_PATH=/Users/parav/.gem/ruby/2.7.7:/Users/parav/.rubies/ruby-2.7.7/lib/ruby/gems/2.7.0
project_dir=/Users/parav/vscode
project=/Users/parav/vscode/teacher
project_repo=https://github.com/nighthawkcoders/teacher.git
posts=/Users/parav/vscode/teacher/_posts
notebooks=/Users/parav/vscode/teacher/_notebooks
LANG=en_US.UTF-8
_=/usr/bin/env
(base) parav@Paravs-MacBook-Air teacher % source /tmp/variables.sh
(base) parav@Paravs-MacBook-Air teacher % cd $project
(base) parav@Paravs-MacBook-Air teacher % echo "show the secrets of .git"
show the secrets of .git
(base) parav@Paravs-MacBook-Air teacher % cd .git
(base) parav@Paravs-MacBook-Air .git % ls -l
total 56
-rw-r--r--   1 parav  staff     21 Aug 23 12:19 HEAD
-rw-r--r--   1 parav  staff    312 Aug 23 12:19 config
-rw-r--r--   1 parav  staff     73 Aug 23 12:19 description
drwxr-xr-x  15 parav  staff    480 Aug 23 12:19 hooks
-rw-r--r--   1 parav  staff  11702 Aug 23 12:19 index
drwxr-xr-x   3 parav  staff     96 Aug 23 12:19 info
drwxr-xr-x   4 parav  staff    128 Aug 23 12:19 logs
drwxr-xr-x   4 parav  staff    128 Aug 23 12:19 objects
-rw-r--r--   1 parav  staff    112 Aug 23 12:19 packed-refs
drwxr-xr-x   5 parav  staff    160 Aug 23 12:19 refs
(base) parav@Paravs-MacBook-Air .git % cat config
[core]
	repositoryformatversion = 0
	filemode = true
	bare = false
	logallrefupdates = true
	ignorecase = true
	precomposeunicode = true
[remote "origin"]
	url = https://github.com/nighthawkcoders/teacher.git
	fetch = +refs/heads/*:refs/remotes/origin/*
[branch "main"]
	remote = origin
	merge = refs/heads/main
(base) parav@Paravs-MacBook-Air .git % cd /tmp
(base) parav@Paravs-MacBook-Air /tmp % file="sample.md"
if [ -f "$file" ]; then
    rm $file
fi
(base) parav@Paravs-MacBook-Air /tmp % tee -a $file >/dev/null <<EOF
heredoc> This introductory paragraph and this line and the title above are generated using tee with the standard input (<<) redirection operator.
- This bulleted element is still part of the tee body.
heredoc> EOF
(base) parav@Paravs-MacBook-Air /tmp % echo "- This bulleted element and lines below are generated using echo with standard output (>>) redirection operator." >> $file
(base) parav@Paravs-MacBook-Air /tmp % echo "- The list definition, as is, is using space to seperate lines.  Thus the use of commas and hyphens in output." >> $file
(base) parav@Paravs-MacBook-Air /tmp % actions=("ls,list-directory" "cd,change-directory" "pwd,present-working-directory" "if-then-fi,test-condition" "env,bash-environment-variables" "cat,view-file-contents" "tee,write-to-output" "echo,display-content-of-string" "echo_text_>\$file,write-content-to-file" "echo_text_>>\$file,append-content-to-file")
(base) parav@Paravs-MacBook-Air /tmp % for action in ${actions[@]}; do
for> action=${action//-/ }
for> action=${action//,/: }
for> action=${action//_text_/ \"sample text\" }
for> echo "    - ${action//-/ }" >> $file
for> done
(base) parav@Paravs-MacBook-Air /tmp % echo "File listing and status"
File listing and status
(base) parav@Paravs-MacBook-Air /tmp % ls -l $file
-rw-r--r--  1 parav  wheel  783 Aug 23 12:32 sample.md
(base) parav@Paravs-MacBook-Air /tmp % wc $file
      14     128     783 sample.md

Command	Action
cd	change directory
ls	list directories
echo	print out input
pwd	present working directory
cat	show contents of file

-v can help check the version, if not installed, it will not show. ‘which’ will show the version

Push commits and update to the github repository