Cross-platform editing: Atom works across operating systems. You can use it on OS X, Windows, or Linux. Built-in package manager: Search for and install new packages or start creating your own from within Atom. Smart autocompletion: Atom helps you write code faster with a smart, flexible autocomplete. File system browser: Easily browse and open a single file, a whole project, or multiple projects in one window. Multiple panes: Split your Atom interface into multiple panes to compare and edit code across files. Find and replace: Find, preview, and replace text as you type in a file or across all your projects. Packages: You choose from thousands of open source packages that add new features and functionality to Atom—or build a package from scratch and publish it for everyone else to use. Themes: Atom comes pre-installed with four UI and eight syntax themes in both dark and light colors. If you can't find what you're looking for, you can also install themes created by the Atom community or create your own. Customization: It's easy to customize and style Atom. You can tweak the look and feel of your UI with CSS/Less and add major features with HTML and JavaScript. Under the hood: Atom is a desktop application built with HTML, JavaScript, CSS, and Node.js integration. It runs on Electron, a framework for building cross platform apps using web technologies.

• Undo/Redo • Color syntax highlighting • Pull-down Menus showing key assignments • Context-sensitive Help • Pop-up file directory pick list • Ability to save/restore editing sessions, including files, windows, cursor positions, blocks, history, recently-edited files • Can emulate other editors/word processors • Pop-up history windows • Embedded programming language for extensive customization • Modern-style syntax • Offers automatic start-up macro • Features procedures with parameter passing, local and global variables • Provides access to editor, screen, user-interface, system functions • Includes macro language debugger • 30,000+ lines of macro source included • Accommodates macro files up to 64k in size, with up to 60 macro files loaded in a session • Allows access to DLLs • Customizable pull-down menus and menu bars allow you to create your own menus • Menu-driven customization facility that allows changing of editing preferences • Configurable user interface and color settings • Reassignable keys • Configurable mouse wheel support* • Selectable fonts and font sizes • Optional printing of line numbers • Single-, double-, and triple-spaced printing • Top, bottom, left and right margins • Ability to pause between pages • Support for page numbers, headers and footers • Option to print selected pages • Copy, Cut, or paste to/from Windows Clipboard • Support for CUA-style (shift-cursor-key) block marking • Support for column, line, character blocks • Mark word or paragraph • Case-change feature - upper, lower, flip, capitalize • Options to move, copy, delete, cut, append, overlay, print, save, fill, reformat, in/outdent, unindent, quote/comment • Ability to sum a column of numbers • Support for long filenames, UNC paths • Support for line lengths to 16,000 characters • Option to search subdirectories for matching files when loading or selecting files • "Drag and Drop" file support* • Virtual memory support for large files • Simultaneous editing of multiple files • Multiple horizontal and vertical windows for viewing files, with synchronized scrolling option • Configurable option to load files matching a wildcard specification • Default extensions for loading files • Filename-completion option available at any prompt requesting a filename • Option to save all files • Ability to edit files in hex and binary modes • Configurable file-end terminator • Configurable line-end terminator (allows editing of UNIX/MAC files)