Rsync compatibility
For examples, start with Use rsync-style commands.
See syq rsync for all accepted options.
Differences to check before switching
| Area | Syq behavior |
|---|---|
| Filters | Gitignore syntax via --syq-ignore / --syq-ignore-from; rsync filters are unsupported |
| Deletion timing | Extras are deleted after copying; no delete-before or delete-during mode |
Positive --max-delete N | Deletes nothing if the plan exceeds N; rsync deletes up to N |
| Destination collisions | Distinct sources claiming the same destination fail before copying |
--ignore-existing | Keeps an existing non-directory even where the source would create a directory |
| Type changes | Refuses replacement between a directory and any non-directory, even when the directory is empty |
--update | Checks mtimes only for regular files; replacements between non-directory types still occur |
| Resume | Always keeps syq partial files; cannot reuse rsync partials |
| Delta transfer | Reuses matching blocks at the same offsets; does not find shifted blocks |
--rsync-path PATH | Exact syq executable path, not a shell fragment |
| Remote-to-remote | Refused; use native syq cp |
Scan and copy errors prevent deletion. A destination that contains its source
on the same host cannot be pruned. Preview deletion scope with --dry-run -v;
see deletion rules.
The compatibility command uses rsync’s default size-and-whole-second timestamp
quick check. Native syq cp also compares fractional seconds at the precision
suggested by the destination timestamp; see timestamp matching.
Use -c to compare contents when size and timestamp match; source timestamps
are preserved, so ordinary clock skew does not require the source timestamp
to be newer.
Syq uses numeric IDs and always keeps partial files, so --numeric-ids and
--partial are accepted no-ops. -P enables progress. Compression is on by
default; -z does not enable anything extra. -B / --block-size changes
syq’s comparison and reuse block size; see the tuning table
for its default and allowed range. Values outside that range are rejected.
Unsupported features
| Feature | Options or syntax |
|---|---|
| Rsync filter rules | --exclude, --include, --filter |
| Hard links, ACLs, xattrs, sparse files | -H, -A, -X, -S |
| Backup and alternate destination trees | --backup, --backup-dir, --suffix, --link-dest, --compare-dest, --copy-dest |
| Following descendant links | -L, --copy-links, --copy-unsafe-links, -k, --copy-dirlinks, -K, --keep-dirlinks |
| Link filtering or rewriting | --safe-links, --munge-links |
| Other placement and filesystem controls | -R / --relative, --partial-dir, -x / --one-file-system |
| Early deletion | --delete-before, --delete-during, --force |
| Other comparison and output controls | --size-only, -I / --ignore-times, --modify-window, --chmod, --log-file, -i / --itemize-changes |
| Daemon connections | rsync://, host::module |
Unsupported common flags are rejected with an explanation. Selected symlink
targets are copied unchanged. --insecure-links does not enable any of the
unsupported descendant-link options.
File-list parsing and help
--files-from cannot combine with syq ignore rules or deletion. A listed
source whose parent is a symlink fails that entry with exit 23, without
creating its implied destination parent. --insecure-links only relaxes the
ownership check on symlinks in typed local paths; it does not allow symlink
traversal beneath a selected source, including entries from --files-from.
Other parsing differences:
..components are rejected rather than clamped at the source root.dir/anddirselect the same entry. Neither selects contents unless-ris explicitly supplied;-aalone does not enable recursion here..and/are rejected as root entries.- Use
--from0for NUL separators;-0is unsupported.
Blank entries and comment-looking names starting with # or ; are ignored
in both separator modes. Use ./#name for a literal name. The paths are relative to one source directory; destination parents are
created as needed.
-h alone does not show help; use --help or --help-all.
Syq extensions
Most syq-specific options carry a --syq- prefix. Common ones are
--syq-ignore and --syq-ignore-from.
Use --integrity-checking to choose comparison and
transfer hashes in rsync mode. -c selects content comparison.
Filters are last-match-wins with ! re-inclusion, unlike rsync’s first-match
rules. Check the gitignore examples when
converting a filtered command.
The compatibility tests record comparison evidence and version-specific details.
Compare without copying
syq rsync -ancv project/ backup/
Compares contents without copying and lists planned changes.
Performance controls use --performance-tuning; resource ceilings use
--resource-limits. The standard rsync spelling --bwlimit remains available
in syq rsync, as does --checksum for BLAKE3 content comparison.