Scripting with Git – in Shell Scripting

What You’ll Learn 📚

• Core concepts of Git and shell scripting
• Key terminology and definitions
• Simple to complex scripting examples
• Common questions and troubleshooting tips

Introduction to Git and Shell Scripting

Before diving into scripting, let’s briefly understand what Git and shell scripting are:

Git

Git is a version control system that helps you track changes in your code and collaborate with others. It’s like a time machine for your code! 🚀

Shell Scripting

Shell scripting involves writing scripts to automate tasks in a Unix-like operating system. Think of it as giving your computer a to-do list to make your life easier. 📝

Key Terminology

• Repository: A storage location for your project files and their history.
• Commit: A snapshot of your project’s files at a specific point in time.
• Branch: A separate line of development in your project.
• Merge: Combining changes from different branches.

Getting Started with a Simple Example

Let’s start with the simplest possible example: creating a script to initialize a new Git repository.

#!/bin/bash
# This script initializes a new Git repository
echo "Enter the directory name:"
read dir_name
mkdir $dir_name
cd $dir_name
git init
echo "Git repository initialized in $dir_name"

Enter the directory name:
my_project
Git repository initialized in my_project

Progressively Complex Examples

Example 1: Automating Git Add and Commit

#!/bin/bash
# This script automates adding and committing changes
echo "Enter commit message:"
read commit_message
git add .
git commit -m "$commit_message"
echo "Changes committed with message: '$commit_message'"

Enter commit message:
Initial commit
Changes committed with message: 'Initial commit'

Example 2: Creating and Switching Branches

#!/bin/bash
# This script creates a new branch and switches to it
echo "Enter branch name:"
read branch_name
git checkout -b $branch_name
echo "Switched to new branch '$branch_name'"

Enter branch name:
feature-xyz
Switched to new branch 'feature-xyz'

Example 3: Merging Branches

#!/bin/bash
# This script merges a specified branch into the current branch
echo "Enter branch name to merge:"
read branch_name
git merge $branch_name
echo "Merged branch '$branch_name' into current branch"

Enter branch name to merge:
feature-xyz
Merged branch 'feature-xyz' into current branch

Common Questions and Answers

1. What is a shell script?

   A shell script is a text file containing a sequence of commands for a Unix-based operating system to execute.

2. Why use shell scripts with Git?

   Shell scripts automate repetitive tasks, saving time and reducing the chance of errors.

3. How do I run a shell script?

   Use the command bash script_name.sh in the terminal.

4. What is the purpose of git init?

   It initializes a new Git repository in the specified directory.

5. How do I check the current branch?

   Use git branch to list all branches and highlight the current one.

6. What happens if I try to merge a branch with conflicts?

   Git will pause the merge and prompt you to resolve conflicts manually.

7. Can I undo a commit?

   Yes, use git reset or git revert depending on your needs.

8. How do I delete a branch?

   Use git branch -d branch_name to delete a branch.

9. What is a remote repository?

   A remote repository is a version of your project hosted on a server, allowing collaboration.

10. How do I push changes to a remote repository?

    Use git push origin branch_name to push changes.

11. What is a pull request?

    A pull request is a way to propose changes to a repository, typically used in collaborative environments.

12. How do I clone a repository?

    Use git clone repository_url to copy a repository to your local machine.

13. What is a commit hash?

    A unique identifier for each commit, used to reference specific changes.

14. How do I view commit history?

    Use git log to see a list of past commits.

15. What is a staging area?

    A place where changes are prepared before committing.

16. How do I undo changes in the working directory?

    Use git checkout -- file_name to discard changes.

17. What is the difference between git pull and git fetch?

    git fetch updates your local repository with changes from the remote, while git pull also merges them into your current branch.

18. How do I resolve merge conflicts?

    Manually edit the conflicting files, then use git add and git commit to finalize the merge.

19. What is a .gitignore file?

    A file specifying which files or directories should be ignored by Git.

20. How do I create a .gitignore file?

    Create a file named .gitignore in your repository’s root and list the files/directories to ignore.

Troubleshooting Common Issues

If you encounter issues, don’t panic! Here are some common problems and solutions:

• Permission Denied: Ensure your script has execute permissions using chmod +x script_name.sh.
• Command Not Found: Check if Git is installed and added to your system’s PATH.
• Merge Conflicts: Manually resolve conflicts by editing the files, then commit the changes.
• Detached HEAD: Use git checkout branch_name to switch back to a branch.

Practice Exercises

Try these exercises to reinforce your learning:

1. Create a script to automate pushing changes to a remote repository.
2. Write a script to list all branches and their last commit messages.
3. Develop a script to automate the creation of a new feature branch and push it to a remote repository.

Remember, practice makes perfect! Keep experimenting and don’t hesitate to refer to the Git documentation for more information.

Happy scripting! 🎉