Back up and synchronise

Two actions to bring two folders into agreement, and one and the same dialog: Compare the two panels. It shows what it is going to do before doing it.

Back up — F10

Mirror mode: one panel prevails. The rule is written in the dialog, in plain words: “I overwrite what has changed, and I delete what is extra.” At the end, the copy is the image of the original — including for what should not have been there.

The one that prevails is named — “the left panel prevails” — and “Reverse the direction” swaps them without leaving the dialog. It is the first thing to check: it is the only setting that decides what will be deleted.

Synchronise — F11

The two folders meet instead of one erasing the other. Each difference carries its action, and each action can be unticked:

• Copy to the left / to the right
• Delete on the left / on the right
• Leave alone — the row stays, intact on both sides.

The summary counts what is ticked: “42 actions, including 3 deletions”, and the scope is recalled — “limited to what is ticked”.

What makes two files the same

Under mirror mode, two boxes change the question asked of each pair of files. Ticking them redoes the comparison: they do not sort a list, they decide what counts as a difference.

• Nothing ticked — the date, then the size. Two seconds of tolerance: FAT rounds, and two volumes do not have the same clock. Not a single byte is read.
• Ignore the date — the size alone. For a copy that has lost its dates: an FTP upload, a trip through a stick, a restore. Without it, everything came out as different at every backup.
• Compare the content — the bytes, and only at equal size: two different sizes are told apart without reading anything. The only verdict that is never wrong, and the only one that costs — both files are read in full. The date no longer has a say: the box above shows it.

The date decides the direction, never the difference. Once two files are declared different, it is the more recent one that is proposed to keep, whatever the rule. With equal dates, nobody decides: the row stays on Leave alone, and carries the note content differs when everything matches except the bytes.

Before starting

A last dialog announces the figures and does not hide the worst: “120 items written, and 3 deleted permanently — without going to the recycle bin”. This is the moment to say no.

What else it says

• Both folders are identical — nothing to do, and that is an answer.
• Both panels show the same folder — the action makes no sense.
• 2 unreadable folders, left untouched: what could not be read is not deleted for all that. A blind comparison that erases is exactly what a backup must not do.

Every day, without thinking about it

Schedule…, in the same dialog, turns this backup into a task of the system’s scheduler: set up the way the dialog is, it comes back at the set time, even when signed out. See Scheduling an action.

Meneaufile manual, in English.