Command reference for programmers

 requirements.txt file for installing python packages

You can use a requirements.txt file to install multiple Python packages at once.

 1. Create a requirements.txt file

This file should list all the packages you want to install, with each package on a new line. Example:

makefile

numpy==1.23.1
pandas>=1.5
requests
matplotlib<=3.6

• == specifies an exact version.
• >= installs a minimum version.
• <= installs up to a certain version.

2. Install packages using requirements.txt

Run the following command in your terminal or command prompt:

pip install -r requirements.txt

This will install all the packages listed in the file.

3. Generate a requirements.txt file (Optional)

If you already have packages installed in your environment and want to create a requirements.txt file, run:

pip freeze > requirements.txt

This will generate a list of installed packages with their versions. Please note that output may be a dump of all packages in the environment that may not be very useful. 

Creating and using virtual environment in python

Using minoconda:

There is a detailed post here, for quick reference here is the command to be used:

conda create --name myenv python=3.9 conda activate myenv

mentioning python and its version is not mandatory if you want to use a common python

Using built-in python virtual environment:

python -m venv myenv

myenv\Scripts\activate     # On Windows

Github commands quick reference

Clone:

git clone https://github.com/username/repo.git

Create new repo (local):

git init

[or git init --initial-branch=main # If default branch name to be main]

git add .

git commit -m "Initial commit"

git branch -M main

git remote add origin https://github.com/username/repo.git

git push -u origin main

Working with changes:

git status         # Check status of changes

git add file.py    # Stage a file

git add .          # Stage all changes

git commit -m "Message"  # Commit changes

git push origin main     # Push to remote repo

Pull latest change:

git pull origin main  # Get latest changes

Working with branches:

git branch feature-branch       # Create new branch

git checkout feature-branch     # Switch to branch

git switch feature-branch       # Alternative (modern)

git checkout -b new-feature     # Create & switch

git push -u origin new-feature  # Push branch to remote

Merge branches:

git checkout main

git merge feature-branch

git push origin main