An app from Excelano
Slipcase Open
Open a container straight through.
The companion to Slipcase Desktop that stays out of the way: double-click a .slpc container and its content file opens in whatever application your computer already uses for that kind of file, with no window of its own in between. Edit it there, save, and the change is written back inside the container. For macOS, Windows, and Linux.
Also on macOS through Homebrew and on Linux via apt, with the code on GitHub. Its sibling, which shows a container rather than opening through it, is Slipcase Desktop.
It gets out of the way of the document
Slipcase Desktop shows you a container — its verdict, its flyleaf, the content file inside. Slipcase Open does the opposite: it hands you the document and disappears. Double-click a .slpc and the content file opens in the application your computer already uses for that kind of file. The flyleaf travels on untouched, and anything else in the container the tool does not recognize is preserved.
Opening a container starts a session. The content file is copied into your own state directory, that directory is watched, and every save the watcher sees is repacked into a fresh container and swapped over the original in one step, so an interruption cannot leave a half-written container behind. Sessions are explicit: they are listed, they are closed by hand, and one that outlives a crash is offered back on the next launch rather than written back unseen — because the tool was not watching when the process died and cannot tell a finished save from a partial one.
A container that arrived from elsewhere keeps its mark: the tool carries it onto the content file and back onto the container, the way Slipcase Desktop does, so your system treats it with the caution it gives anything from outside.
Alongside Slipcase Desktop
The two claim the same file association deliberately. Whichever was installed last opens on double-click, and the other stays one click away in the Open With menu, so a machine can have both and choose per file: Slipcase Desktop when you want to read a container and edit its flyleaf, Slipcase Open when you just want the document. Both go through slpc, the reference library, and neither parses a container itself.
How to get it
Windows
Slipcase Open is on the Microsoft Store. Install it the way you install any other app — updates arrive through the store.
macOS
It installs through Homebrew rather than the Mac App Store, because the sandbox that store requires would cost the tool the write-back path it exists for:
brew install --cask excelano/tap/slipcase-open
Debian and Ubuntu
It is in the same apt repository as Slipcase Desktop, and it depends on slipcase-common, which declares the media type and ships the icon a container is drawn with. Apt pulls that in:
curl -fsSL https://excelano.com/apt/setup.sh | sudo sh sudo apt install slipcase-open
From source
Slipcase Open is written in Rust and builds with a Rust toolchain alone. The README covers building and the desktop integration.
Privacy
Like Slipcase Desktop, Slipcase Open makes no network connection, has no account, and collects nothing. It does write more to your own disk than its sibling, by design — the content file lives in your state directory for the life of a session so a reboot cannot lose an unsaved edit — and its privacy statement lists all of it. The source is at github.com/excelano/slipcase-open, and the statement is written to be checked against it.
Behind the tool
Slipcase Open is one corner of Slipcase, a container format I designed so a file's description travels inside the file rather than in a database on someone else's computer. Attaching a description to a document without changing the document, and without scattering that description across filenames and sidecar files, is a problem that keeps coming up in the data and migration work I do for clients.
If that is a snag your team keeps hitting, it is the kind of work I am glad to take on.