--- title: DOpus description: MixOS's twin-pane file manager — two folder trees side by side, Places and Properties sidebars, drag and drop between panes, menus and keys for every action, and a Bus surface for agents that reads and navigates but never changes files. --- # DOpus DOpus is MixOS's file manager: two panes side by side, each a folder tree, with a Places sidebar on the left and a Properties sidebar on the right. The name is a nod to Directory Opus on the Amiga, whose twin panes it keeps. ## The window - **Two panes.** Each shows one folder as a tree with Name, Size and Modified columns; columns that do not fit are hidden, Modified first. One pane is active; Switch Pane (Tab) moves between them, and copy and move always go to the other pane. Drag the divider to change the split. - **The path field** at the top of each pane always shows where it is. Click it, type a path and press Enter to go there; `~` is your home, and a file path opens the folder that holds it. - **The tree.** A chevron or a double-click opens a folder in place; another collapses it. Double-click a file to open it in its default application. - **Selecting.** Click a row to select it, Ctrl-click to add or remove one, Shift-click for a range. The arrow keys, Home and End move the selection. - **Sorting.** Click a column header to sort by it, ascending first; click it again to reverse. - **Places** lists Home, the filesystem root and your Desktop, Documents, Downloads, Music, Pictures and Videos folders, where they exist. Its toggle sits left of the left pane's path field. - **Properties** shows the selected item: kind, size, dates, permissions, owner and path, under a preview of a file when one can be made. Its toggle sits right of the right pane's path field. - **Previews** (View › Previews, per pane, on by default) are thumbnails from the desktop's shared thumbnail cache, made by the thumbnailers installed on the system (the same ones GNOME and COSMIC use). A type with no thumbnailer keeps its icon. Files on network, FUSE and automounted filesystems (NFS, SMB, sshfs, ntfs-3g and the like) keep their icons too, unless `remote_previews: true` is set in the configuration (below). A file whose filesystem stops answering keeps its icon rather than holding up the previews of the others. - **Icons** show what a folder or file holds: your well-known folders have their own, and files are grouped by their MIME type (document, code, image, audio, video, archive, spreadsheet, presentation, font, disk image, program, shell script). - **Drag and drop.** Drag rows from one pane onto the other, or onto a folder in it, and choose Move Here, Copy Here or Cancel. - **Right-click** a row or a pane's background for the actions that apply there. Deleting asks first, and naming a new folder or a rename is checked before anything happens. Copies, moves and deletes run in the background, and the status line says how they ended. ## Menus and keys The menus hold every action except moving the selection (the arrow keys, Home and End) and the quick theme keys (Ctrl+Alt+D for light or dark, Ctrl+Alt+1 to 6 for a scheme; View › Theme has the full choice). Help › Keyboard Shortcuts lists every key in force. | Menu | Action | Keys | |---|---|---| | File | Open | Enter | | | New Folder | Ctrl+Shift+N | | | Rename | Ctrl+E | | | Copy to Other Pane | Ctrl+C | | | Move to Other Pane | Ctrl+X | | | Delete | Delete | | | Quit | Ctrl+Q | | View | Places, Properties | Ctrl+B, Ctrl+I | | | Hidden Files | Ctrl+H | | | Refresh | Ctrl+R | | | Sort by Name, Size, Modified | Ctrl+1, Ctrl+2, Ctrl+3 | | | Theme | (this window's look; the session's by default) | | Go | Back, Forward | Alt+ArrowLeft, Alt+ArrowRight | | | Parent Folder | Backspace, Alt+ArrowUp | | | Home | Alt+Home | | | Location… | Ctrl+L | | | Switch Pane | Tab | | Help | Keyboard Shortcuts | Ctrl+/ | To change a key, set it in the desktop profile: the binding applies at once, and DOpus's defaults stay for every action you leave alone. For example, `settings.apply` with `keymaps.dopus.nav.parent: ["Ctrl+U"]` makes Ctrl+U the parent-folder key, an empty list leaves an action without a key, and a reset of `keymaps.dopus` restores the defaults. See [key bindings are desktop settings](../docs/decisions/2026-10-11-keymaps-in-settings.md). ## What it remembers The two panes' folders, sorting and hidden-files setting, which pane was active, the split, and the sidebars' state and widths are kept in `config.conf.mix` in DOpus's own directory (by default `~/.local/state/mixos/apps/dopus/config/`). `dopus --print-config` shows the configuration it would use. One setting lives only there: `remote_previews` (default `false`) makes previews of files on network, FUSE and automounted filesystems too. ## For agents DOpus answers on the Bus as `dopus` (schema `dopus.v1`). | Verb | Arguments | Answer | |---|---|---| | `dopus.ping`, `dopus.describe`, `dopus.info` | | liveness, the control surface, version and build | | `dopus.state` | | both panes (path, sort, hidden files, previews, selection, rows, status) and the sidebars | | `dopus.open` | `paths` (one per pane), or one path and `pane` | goes there | | `dopus.action` | `id`, `pane` (`left`, `right` or `active`) | runs one action | | `dopus.actions.list` | | every action, its keys in force and whether it can run now | | `dopus.theme.set` | `scheme`, `mode` | this window's look | | `dopus.quit` | | closes the window | **File operations are keyboard-only.** `dopus.action` refuses every `file.*` action (`FORBIDDEN`). Input played through the drive verbs (`dopus.ui.*`) is held to the same rule: while it runs, file actions and opening files are refused, and a delete, name or drop dialog can be dismissed but not accepted. The rule holds for the whole time drive input runs, so a key you press yourself in that moment is refused too; press it again after. An agent reads, navigates, sorts and selects through DOpus, but never creates, renames, moves, copies, deletes or opens files through it. The window is drivable like every MixOS app, including its menus: see [driving an app](../docs/drive.md) (`dopus.ui.*`, `dopus.window`). The verbs are registered in `docs/docs/spec/bus/verbs.conf.mix`. Each command run from a menu, a key, a sidebar button or an accepted `dopus.action` is published on `dopus.command.executed`, with how it was reached (`menu`, `shortcut`, `ui` or `bus`; [executed commands](../docs/decisions/2026-10-11-executed-commands.md)). A refused action is not published. `dopus --headless` runs the core and the Bus port without a window, for tests: the same verbs, minus those that need a window. It publishes its accepted `dopus.action` runs on `.command.executed` too.