captains-deck.com ~/guides/diff G.02.C · 5 min read ↑ updated 2026-01-22 --:--:--
Intermediate G.02.C 5 min read

Two folders, one diff.

F9 turns the dual pane into a side-by-side diff — every file, every line, side-by-side. Then merge in either direction with a single key.

Launching diff

Press F9 with both panes pointed at folders you want to compare, or with two files selected (one in each pane). Captain’s Deck picks the right mode automatically.

Directory diff

The directory view shows every file, marked with one of:

=Identical (hash match)
Both exist, contents differ
LOnly on the left
ROnly on the right

Filter the view to focus on differences only with D, or show every file with A.

File diff

Enter on a differing pair opens the file diff — a side-by-side text view with synced scrolling. Useful keys:

  • n / p — next / previous change
  • w — toggle ignore whitespace
  • c — toggle ignore case
  • u — switch to unified view (single column)

Merging changes

The diff viewer groups consecutive changed lines into hunks — one block of related changes. Use these keys to walk through them and decide each one:

  • n — next hunk
  • p — previous hunk
  • >take right: the left file adopts the right side’s version of this hunk
  • <take left: the right file adopts the left side’s version
  • x — skip this hunk (both files stay as they are)

Decisions are kept in memory until you commit them. The status bar shows the current hunk number and which way (if any) you’ve resolved it.

When you’re happy, click Save Merged in the toolbar. Captain’s Deck writes both files at once (only the side you actually changed gets touched) and re-runs the diff so you can see the new state. Close the panel without saving and nothing is written.

Folder sync

From the directory diff, press S to open the Sync wizard. Pick:

  • Mirror left → right — make right match left exactly (with delete confirmation)
  • Mirror right → left — the reverse
  • Bidirectional — newest wins per-file (great for laptop ↔ NAS sync)

Preview the operation list before committing. Each action is queued so you can untick individual rows.

Tweaks

Theme
Motion