Folder Synchronization

Diffoniq can synchronize two folders — interactively from a directory comparison, or headless from the command line for scripts and the Windows Task Scheduler. In both cases the same compare engine as the interactive directory comparison (including the persistent hash cache and rename/move detection) decides what to do, then a plan of copy, rename and delete operations is carried out. For driving /sync from scripts or an AI assistant, see Scripting and AI Assistants.

The Synchronize dialog

In a folder comparison, File > Synchronize... opens a preview built from the comparison already on screen — no second scan. Pick the mode (Mirror or Update, see below), the direction (left to right or right to left) and the deletion policy; the action list and the summary line follow immediately. Execute carries out exactly the listed actions with a progress dialog that can be canceled between actions; afterwards the comparison is refreshed from disk.

A pair whose content hash is still being computed (or was aborted) is listed as skipped — it is never blindly copied. Let the background compare finish, then reopen the dialog.
Deletions go to the Recycle Bin unless Permanent is checked. Network targets have no recycle bin — deletions there are always permanent (the result message says so).
Execute needs a full-depth comparison: with Look in Subfolders off (or a limited subfolder level) the button stays disabled — a sync built from a partial scan could delete folders whose contents were never copied. The Single files/Subdirectories view filters only hide rows; they do not limit the sync.
The preview is free to use in the trial; Execute requires a licensed copy.

Command line (`/sync`)

The headless twin of the dialog — it prints nothing and reports through an exit code and a log file:

Diffoniq /sync <left> <right> (--mirror | --update)
        [--execute] [--content] [--permanent]
        [--log <file>] [compare switches]

The shell does not wait by itself: Diffoniq is a windowed program, so a bare call returns immediately — use start "" /wait (cmd) or Start-Process -Wait (PowerShell, recipes in Scripting and AI Assistants); the log file is written to a temporary name and appears only when the run is complete.

Modes

`--mirror`	The right folder becomes a mirror of the left one: new and changed files are copied, files existing only on the right are deleted, and files recognized as renamed or moved are renamed on the right instead of being copied again.
`--update`	Copy only: new and changed files go left → right. Nothing is ever deleted or renamed on the right.

On the command line the direction is always left → right; to synchronize the other way, swap the two path arguments. Both paths must be folders — archives can be compared and viewed, but not used as a synchronization root.

Safety

Without --execute nothing is touched. The run is a dry run: the planned operations are written to the log file and the exit code reports whether differences exist. Add --execute — typically after checking the dry-run log once — to apply the plan.
Deletions go to the Recycle Bin by default. --permanent deletes for good. Network drives have no recycle bin; deletions there are always permanent (noted in the log).
Errors never abort the run. A locked or read-only file is recorded, the remaining operations continue, and the run finishes with exit code 2 and an error list in the log. Read-only attributes are never stripped.
A folder that cannot be read stops the run before it starts (exit code 3, the folder is named in the log). A tree with a hole in it must never become a plan — a mirror would read the hole as “missing on this side” and delete the other side’s copy.
Symbolic links and junctions are not followed — they are logged as skipped.

What counts as “changed”

By default a file pair is compared the quick way — by size and timestamp, honoring the Ignore Date/Time/Size switches. With --content the decision is made by file content instead: equal-sized pairs are hash-verified, so a touched-but-identical file is not copied and a same-size/same-date change is still caught. Repeat runs — the scheduler scenario — resolve those hashes from the hash cache almost for free.

Result: exit code and log

/sync prints nothing. The result is the process exit code plus a log file — ideal for schedulers, which capture exactly these two things:

`0`	No differences — nothing to do
`1`	Differences found; dry run: reported · with `--execute`: synchronized successfully
`2`	Finished with errors (partially synchronized)
`3`	Invalid arguments, or aborted before any operation

The log is written to %APPDATA%\Diffoniq\sync\sync_YYYYMMDD_HHMMSS.log (the 30 newest logs are kept) unless --log <file> names a different location.

Scheduling a nightly sync

Create a scheduled task that runs the sync every night at 02:30:

schtasks /create /tn "Nightly backup sync" /sc daily /st 02:30 ^
  /tr "\"C:\Program Files\Diffoniq\Diffoniq.exe\" /sync D:\work \\nas\backup\work --mirror --execute --log D:\logs\work-sync.log"

Tip: run the same command once without --execute and review the dry-run log before arming the task.

Licensing

During the trial period only dry runs are available; --execute requires a licensed copy and otherwise exits with code 3 (a note is written to the log — no dialog interrupts a scheduled run).

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