> ## Documentation Index
> Fetch the complete documentation index at: https://docs.allthingslinux.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Glossary

> Definitions of terms used throughout the atl.sh documentation.

| Term                  | Definition                                                                                                                                      |
| --------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------- |
| **AIDE**              | Advanced Intrusion Detection Environment — file integrity checker that detects unauthorized changes to system files                             |
| **auditd**            | Linux audit daemon — logs security-relevant system events based on configurable rules                                                           |
| **Borgmatic**         | Wrapper around BorgBackup that simplifies backup configuration and scheduling                                                                   |
| **certbot**           | Let's Encrypt client that automates TLS certificate issuance and renewal                                                                        |
| **cgroup**            | Control group — Linux kernel feature for limiting and isolating resource usage (CPU, memory, processes) per user or process group               |
| **CGI**               | Common Gateway Interface — protocol for web servers to execute scripts and return dynamic content                                               |
| **chroot**            | Change root — restricts a process's view of the filesystem to a subdirectory                                                                    |
| **DocBase**           | Molly-brown's root directory for serving Gemini content                                                                                         |
| **efingerd**          | Extensible finger daemon — runs shell scripts to handle finger protocol queries                                                                 |
| **Fail2ban**          | Intrusion prevention tool that bans IPs after repeated authentication failures                                                                  |
| **fcgiwrap**          | FastCGI wrapper that executes CGI scripts via the FastCGI protocol                                                                              |
| **Gemini**            | Lightweight internet protocol (port 1965) — simpler than HTTP, uses TLS, serves gemtext documents                                               |
| **gemtext**           | Gemini's markup format — line-oriented, no inline formatting, links on their own lines                                                          |
| **Gopher**            | Internet protocol from 1991 (port 70) — hierarchical menu system, predecessor to the web                                                        |
| **Gophernicus**       | Modern Gopher server with tilde user support and automatic directory listings                                                                   |
| **gophermap**         | Gopher menu file — tab-separated entries defining links, text, and directory structure                                                          |
| **HomeDocBase**       | Molly-brown setting that maps tilde URLs to user subdirectories within DocBase                                                                  |
| **LOLBin**            | Living Off the Land Binary — legitimate system tool that can be abused for malicious purposes (e.g., `curl`, `wget`, `nc`)                      |
| **MITRE ATT\&CK**     | Framework of adversary tactics and techniques — used to tag auditd rules                                                                        |
| **molly-brown**       | Gemini protocol server written in Go — serves capsules with tilde user support                                                                  |
| **MOTD**              | Message of the Day — text displayed to users on SSH login                                                                                       |
| **pam\_namespace**    | PAM module that creates per-session isolated directories (private `/tmp`)                                                                       |
| **PAM**               | Pluggable Authentication Modules — Linux framework for authentication, session setup, and resource limits                                       |
| **pubnix**            | Public-access Unix system — a shared server where community members get shell accounts                                                          |
| **skel**              | Skeleton directory (`/etc/skel/`) — files copied to every new user's home directory on account creation                                         |
| **socket activation** | systemd feature where a service starts on-demand when a connection arrives on its socket, rather than running continuously                      |
| **sub\_filter**       | Nginx directive that modifies response bodies — used to inject the webring widget script                                                        |
| **tilde**             | The `~` character in URLs (e.g., `atl.sh/~username`) — convention from Unix home directory paths, giving rise to "tilde clubs" and "tildeverse" |
| **tildeverse**        | Network of pubnix servers that share the tilde URL convention and community culture                                                             |
| **TOFU**              | Trust On First Use — TLS verification model used by Gemini clients where the first certificate seen is trusted                                  |
| **UFW**               | Uncomplicated Firewall — iptables/nftables frontend for managing firewall rules                                                                 |
| **user slice**        | systemd unit (`user-<uid>.slice`) that contains all processes for a user session, enabling per-user resource limits                             |
| **vsftpd**            | Very Secure FTP Daemon — FTP server with mandatory TLS support                                                                                  |
| **webring**           | Collection of member websites linked in a ring — visitors navigate between sites using next/prev links                                          |
| **XDG**               | freedesktop.org specification for standard user directories (`~/.config`, `~/.local/share`, etc.)                                               |