# TexLive Packages

**Packages extend LaTeX** with new commands and environments. Load them in the preamble (before `\begin{document}`) with `\usepackage{packagename}`. Packages add features like graphics, colors, advanced math, bibliographies, code listings, and much more.

```latex
\documentclass{article}
\usepackage{amsmath}      % advanced math
\usepackage{graphicx}     % include graphics
\usepackage{xcolor}       % colors
\usepackage{hyperref}     % hyperlinks
\begin{document}
% Your content
\end{document}
```

**Common packages:**

`amsmath` — advanced math symbols and environments (align, gather, etc.). Often loaded first if you use anything beyond basic math.

`graphicx` — include images with `\includegraphics`. Required for figures.

`xcolor` — text and background colors with `\textcolor` and `\colorbox`.

`hyperref` — hyperlinks and PDF metadata. Load last (after most other packages) to avoid conflicts. Enables `\url{...}`, `\href{url}{text}`, and internal references.

`listings` — format source code with syntax highlighting and line numbers. Alternative to verbatim for displaying code.

`tikz` — draw diagrams, plots, and graphics programmatically. Powerful but complex; see [[texlive-tikz]].

`geometry` — customize page margins: `\usepackage[margin=1in]{geometry}`.

`fancyhdr` — custom page headers and footers. See [[texlive-headers-footers]].

`natbib` — flexible bibliography system with author-year citations. Alternative to standard BibTeX.

**Package options** are passed in square brackets: `\usepackage[options]{package}`. Example: `\usepackage[T1]{fontenc}` loads T1 font encoding (better for non-English text).

**Installing packages:** Most common packages are included in `texlive-latex-extra`. If a package is missing, install via your package manager: `apt install texlive-latex-extra` (Debian). For newer packages or custom packages, place `.sty` files in the same directory as your `.tex` file or in `~/texmf/tex/latex/`.

**Finding packages:** Search [CTAN](https://ctan.org/) (Comprehensive TeX Archive Network) to find and learn packages. Read package documentation: `texdoc packagename` opens the `.pdf` manual in a viewer if installed.