Git Send Email Tutorial

Overview

The git send-email command is used to send patches via email. This is particularly useful for contributing to projects that use mailing lists for code reviews and patch submissions. The command allows you to send patches created with git format-patch directly to an email address.

What is `git send-email`?

git send-email is a Git command that facilitates sending patches via email. It is used in workflows where patches need to be reviewed or submitted via mailing lists. It integrates with Git’s patch management and email configuration tools to send patches directly from the command line.

Setting Up `git send-email`

Before using git send-email, you need to configure your email settings. This involves setting up the email server and user credentials in your Git configuration.

Configure Email Settings

Set the Email Address:

git config --global user.email "your-email@example.com"

Configure the SMTP Server:

Add your SMTP server details to your Git configuration. Replace placeholders with actual values:

git config --global sendemail.smtpserver "smtp.example.com"
git config --global sendemail.smtpuser "your-username"
git config --global sendemail.smtppass "your-password"

Optional: Configure Other Email Settings:

git config --global sendemail.smtpport "587"
git config --global sendemail.smtpssl "true"

Sending Patches

Once you have configured git send-email, you can send patches via email.

Basic Syntax

git send-email [options] <patch-files>

Example: Sending a Patch via Email

Create a Patch File:

First, create a patch file using git format-patch:
```
git format-patch -1 HEAD
```
This generates a patch file named 0001-<commit-message>.patch.
Send the Patch File via Email:

Use git send-email to send the patch:
```
git send-email 0001-<commit-message>.patch
```
By default, git send-email will prompt for recipient email addresses and other details.

Example: Sending Multiple Patches

To send multiple patches, specify the patch files:

git send-email 0001-patch1.patch 0002-patch2.patch

You can also use a pattern to match multiple patch files:

git send-email *.patch

Examples

Example 1: Sending a Single Patch

Create a Patch:
```
git format-patch -1 HEAD
```

Send the Patch:

git send-email 0001-Add-new-feature.patch

Follow the Prompts:

Enter the recipient email address and any other required information.

Example 2: Sending Patches to a Mailing List

Create Multiple Patches:
```
git format-patch HEAD~3..HEAD
```

Send Patches to a Mailing List:

git send-email --to="patches@project.org" *.patch

Common Use Cases

Contributing to Open Source Projects: Many projects use mailing lists for code reviews and patch submissions.
Submitting Patches for Review: Sending patches for review and discussion before merging them into the main codebase.
Archiving Changes: Sending patches as part of an email thread for record-keeping or documentation.

Summary

git send-email is a powerful tool for sending patches via email, particularly in workflows involving mailing lists and code reviews. By configuring your email settings and using the command, you can streamline the process of sharing changes with collaborators and maintaining a clean and organized codebase.