| name | tar-format |
| description | Reference the Tar/USTAR/PAX/GNU tar archive container format. Use when an AI agent needs to answer questions or make code changes involving tar headers, 512-byte blocks, checksums, typeflags, USTAR prefixes, PAX local/global extended headers, GNU long names/links, sparse entries, wrapper compression, or SharpCompress Tar parsing and writing behavior. |
Tar Format
Use this skill for tar container-format work. It provides a local, SharpCompress-oriented reference for POSIX USTAR, POSIX PAX, GNU tar extensions, and the current SharpCompress Tar implementation.
Reference
- Read references/tar-format.md when the task depends on tar binary layout, header field offsets, typeflag behavior, checksum rules, PAX records, GNU long-name/link records, wrapper compression support, or current SharpCompress Tar support boundaries.
- Treat the reference as an implementation guide, not a standards replacement. It cites POSIX and GNU tar sources, but it also documents SharpCompress-specific behavior and limitations.
- Prefer the SharpCompress support matrix in the reference over generic tar assumptions when changing code. Tar dialect support is intentionally partial in some areas.
Workflow
- Identify which layer is involved: raw tar block/header parsing, POSIX USTAR fields, POSIX PAX metadata, GNU tar extensions, wrapper compression, reader/archive/writer API behavior, or tests.
- Open the relevant section in
references/tar-format.md and use the source-file pointers before changing code.
- For parsing changes, cross-check
TarHeader.cs, TarHeader.Async.cs, EntryType.cs, and matching sync/async tests.
- For writer changes, verify both sync and async file/directory paths and
TarWriterOptions.HeaderFormat behavior.
- For support claims, keep unsupported features explicit: PAX write, sparse reconstruction, device/FIFO semantics, link-writing APIs, and writing
tar.xz, tar.zst, or tar.Z.
