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File preview

Preview opens a read-only view of a remote file right inside the file browser — no download, no shell, no round trip through another app.

  • iPhone and iPad — tap a file row. Tapping a directory still enters it.
  • Mac — double-click a file row, or press Space on the focused row, Finder-style.
  • Both — right-click or long-press a file and choose Preview.

With several rows selected, preview applies to the focused row only.

Text and code open in a read-only viewer with syntax highlighting. The theme follows the system appearance — xcode in light mode, atom-one-dark in dark — and the text is selectable and copyable.

A few deliberate choices:

  • Files over 1 MB render as plain text without highlighting, so a big log still opens instantly.
  • .pem, .key, .crt and friends are treated as text — on a server they are certificate material, not a Keynote deck.
  • Decoding tries UTF-8 first, then falls back to a best guess. If the encoding is uncertain, a banner says so rather than letting misread characters pass silently.

Size policy for text:

Size What happens
Up to 2 MB The whole file is fetched
Over 2 MB The first 512 KB are shown, with Load Entire File in the banner
Over 50 MB The banner offers Download Full File instead — full preview is off the table

Images, PDFs, Office and iWork documents open in Quick Look:

Size What happens
Up to 10 MB Fetched and shown right away
10–50 MB A confirmation asks first: Preview Large File?
Over 50 MB Preview refuses — use a regular download

Media files, archives and compiled binaries have nothing useful to show inline. They get a metadata card instead — name, size, permissions, modified date — with a Download button. And if you know better (“that extensionless file is really a script”), an escape hatch lets you open it as text anyway.

Preview fetches run on their own dedicated connection — the third one a file session may open, after browsing and transfers. They never enter the transfer queue and never appear in the transfer UI, so peeking at a config file can’t stall a download that’s already running.

While a preview is being fetched, its file row shows an inline spinner with progress — select the row again to cancel. Fetched files are cached for the life of the file session, so reopening the same file is instant; the cache is dropped when the file session closes.