Git shortcut command `git prev-branch [steps]`

git-prev-branch-readme.md

Git Previous Branch Command in Node.js

This script provides a custom Git command git prev-branch [steps], allowing you to check out a previously used Git branch by specifying how many steps back in the branch history you wish to go.

Installation

1. Save git-prev-branch.js to a directory in your PATH (e.g. ~/git-prev-branch.js).
2. Make the script executable: chmod +x git-prev-branch.js
3. Rename the script to remove the .js extension: mv git-prev-branch.js git-prev-branch

Usage

To use the command, type git prev-branch [steps], where [steps] is the number of steps back in your branch history. For example, git prev-branch 1 will check out the branch that was used just before the current one.

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Windows Setup

To use this script on Windows, you'll need to have Node.js installed and be able to run Node.js scripts from the command line. Additionally, you will need a way to execute the script as a Git command. Here's how to set it up:

1. Install Node.js: If not already installed, download and install Node.js from nodejs.org.

2. Save the Script: Save the git-prev-branch.js file to a directory.

3. Add to PATH:

   • Right-click on 'This PC' or 'My Computer' on your desktop or in File Explorer.
   • Click 'Properties'.
   • Click 'Advanced system settings'.
   • In the System Properties window, click the 'Environment Variables' button.
   • In the Environment Variables window, select the 'Path' variable in the 'System variables' section, and click 'Edit'.
   • Add the path to the directory where you saved git-prev-branch.js.
   • Click OK in all dialogs to close them.

4. Create a Batch File for Git Command:

   • In the same directory, create a new file named git-prev-branch.bat.
   • Edit the file and add the following line:

     @node "%~dp0git-prev-branch.js" %*
     

   • This batch file allows Git to use the Node.js script as a command.

5. Usage:

   • Open Git Bash or your preferred shell.
   • Use the command as described previously: git prev-branch [step].
   • The [step] parameter works the same as in the Linux/Mac instructions.

This setup allows Windows users to run the script as a Git command. Ensure that the directory containing both git-prev-branch.js and git-prev-branch.bat is in your PATH.

git-prev-branch.js

#!/usr/bin/env node

const { execSync } = require('child_process');

function main() {
    // Check if an argument is provided
    if (process.argv.length < 3) {
        console.error("Please provide a branch step as an argument.");
        process.exit(1);
    }

    // Get the step count and remove minus signs
    const step = parseInt(process.argv[2].replace('-', ''), 10);

    // Extract branch names from the git reflog
    let branches;
    try {
        branches = execSync("git reflog | grep -o 'checkout: moving from [^ ]* to [^ ]*' | awk '{print $6}' | uniq")
            .toString()
            .trim()
            .split('\n');
    } catch (error) {
        console.error("Error extracting branches:", error.message);
        process.exit(1);
    }

    // Get the branch name at the specified step
    const branchName = branches[step - 1];
    if (!branchName) {
        console.error("No such branch found.");
        process.exit(1);
    }

    // Checkout the branch
    try {
        execSync(`git checkout ${branchName}`, { stdio: 'inherit' });
    } catch (error) {
        console.error("Error checking out branch:", error.message);
        process.exit(1);
    }
}

main();