Everyday options
A handful of flags cover most day-to-day situations: previewing what a copy would do before writing a byte, keeping build artifacts like node_modules out of a backup, fitting into a low-memory NAS, or skipping dedup when you already know every file is unique (say, a folder of videos).
Defaults are chosen so that plain fast-copy SRC DST does the right thing — dedup on, verification on, sensible buffers — and each flag below opts out of exactly one behaviour, nothing else.
Examples
Dry run — preview without copying
python fast_copy.py /data /mnt/usb/data --dry-runDisable deduplication (faster for unique files)
python fast_copy.py /data /mnt/usb/data --no-dedupExclude directories
python fast_copy.py /project /mnt/usb/project \
--exclude node_modules --exclude .gitLow-memory system
python fast_copy.py /data /mnt/usb/data --buffer 8Verify a self-update against a known hash
fast-copy --update --update-sha256 <64-hex-from-release-page>
The complete flag list — buffers, threads, hashing, overwrite behaviour and more — is in the options reference.