{"title":"Viewing Changes (git diff)","description":null,"content":"Understanding the differences between commits, branches, and your current working directory is a vital skill in Git.\n\nThe `git diff` command is your go-to tool for visualizing those differences. It helps you see what has been changed, added, or removed, and can be a lifesaver in the development process.\n\n---\n\n# The Basics of `git diff`\n\nAt its core, `git diff` shows the differences between various states of your Git repository.\n\nThis could be differences between:\n\n- Your working directory and the staging area\n- The staging area and the last commit\n- Two different commits or branches\n\nThe command outputs a line-by-line comparison of files, clearly indicating what has changed, been added, or deleted. \n\n### Understanding the Output\n\nThe output of `git diff` can be complex at first glance. Here's a simplified explanation of what to look for:\n\n- **Lines starting with a minus (-)** indicate lines that were removed.\n- **Lines starting with a plus (+)** indicate lines that were added.\n- **Context lines** (lines without a prefix) provide context for the changes.\n\nHere's an example of a `git diff` output:\n\n\n```shell\ndiff --git a/example.txt b/example.txt\nindex 83db48f..f735c1e 100644\n--- a/example.txt\n+++ b/example.txt\n@@ -1,3 +1,3 @@\n-This is the original line.\n+This is the modified line.\n This line remains unchanged.\n Another unchanged line.\n```\n\n\nIn this output:\n\n- The first line shows the file being compared.\n- The `@@` line indicates the hunk of differences, showing context.\n- The line with a minus indicates that the original line has been changed, while the line with a plus shows its new version.\n\n---\n\n# Comparing Different States\n\n### Working Directory vs. Staging Area\n\nOne common use case for `git diff` is to compare your **working directory** with the **staging area**. This shows what changes you have made but haven't yet staged for commit.\n\nThe command for this is simply:\n\n\n```shell\n$ git diff\n```\n\n\nYou can also specify a file:\n\n\n```shell\n$ git diff example.txt\n```\n\n\nThis allows you to see what modifications are pending for that specific file before staging or committing.\n\n### Staging Area vs. Last Commit\n\nAfter staging your changes, you might want to review what you've staged against the last commit. This helps ensure you are committing exactly what you intend to.\n\nTo do this, use:\n\n\n```shell\n$ git diff --cached\n```\n\n\nThe `--cached` flag compares the staging area with the last commit. If you want to see the changes for a specific file, just add the filename:\n\n\n```shell\n$ git diff --cached example.txt\n```\n\n\nThis command is particularly useful just before you run `git commit` to ensure that only the desired changes are included in your next commit.\n\n---\n\n# Comparing Commits\n\n### Between Two Commits\n\nGit allows you to compare any two commits. This can be useful for understanding what has changed over time. The command format is:\n\n\n```shell\n$ git diff \n```\n\n\nYou can specify commit hashes, tags, or branch names. For example:\n\n\n```shell\n$ git diff HEAD~1 HEAD\n```\n\n\nThis compares the last commit (HEAD) to its immediate predecessor (HEAD~1). \n\n### Visualizing Commit Differences\n\nSometimes, using the commit hash directly provides more context. For instance:\n\n\n```shell\n$ git diff a1b2c3d e4f5g6h\n```\n\n\nThis command will show the differences between the two specific commits, allowing you to analyze what changes were made over time.\n\n## Between Branches\n\nYou can also compare entire branches. This is useful when you want to see what changes are in a feature branch that aren't in the main branch. The command is:\n\n\n```shell\n$ git diff main..feature-branch\n```\n\n\nThis shows the changes that would be applied to `main` if you were to merge `feature-branch` into it. \n\n---\n\n# Using Diff Options\n\nThe `git diff` command comes with several options that can enhance its functionality. Here are some noteworthy ones:\n\n### Word Diff\n\nSometimes, you may want to see changes at the word level instead of line level. You can achieve this by using the `--word-diff` option:\n\n\n```shell\n$ git diff --word-diff\n\ndiff --git a/app.js b/app.js\n--- a/app.js\n+++ b/app.js\n@@ -1,3 +1,3 @@\n-console.log('[-Hello-][+Hello, world+]');\n```\n\n\nThis will show insertions and deletions at the word level, making it easier to spot changes in longer lines.\n\n### Stat Option\n\nIf you want a summary of changes, the `--stat` option is very useful. It provides a concise overview of how many files were changed, along with the number of insertions and deletions:\n\n\n```shell\n$ git diff --stat\n\napp.js | 3 ++-\nindex.html | 2 +-\n2 files changed, 3 insertions(+), 2 deletions(-)\n```\n\n\nThis gives you a quick summary before diving deeper into the specifics.\n\n### Color Output\n\nGit typically provides color-coded output, but if you find it difficult to read, you can adjust your settings. To always see color output, you can set:\n\n\n```shell\n$ git config --global color.ui auto\n```\n\n\nThis makes it easier to differentiate between added and removed lines in the output.\n\n---\n\nNow that you understand how to effectively use `git diff`, you are ready to explore `.gitignore`. \n\nIn the next chapter, we will look at how to manage which files should be tracked by Git and which should be ignored, ensuring a clean and efficient workflow.","pageType":"git"}

Viewing Changes (git diff)

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