@node nncp-reass
@section nncp-reass

@example
$ nncp-reass [options] [-dryrun] [-keep] [-dump] [-stdout] FILE.nncp.meta
$ nncp-reass [options] [-dryrun] [-keep] @{-all | -node NODE@}
@end example

Reassemble @ref{Chunked, chunked file} after @ref{nncp-toss, tossing}.

When called with @option{FILE} option, this command will reassemble only
it. When called with @option{-node} option, this command will try to
reassemble all @file{.nncp.meta} files found in @option{NODE}'s
@ref{CfgIncoming, incoming} directory. When called with @option{-all}
option, then cycle through all known nodes to do the same.

Reassembling process does the following:

@enumerate
@item Parses @ref{Chunked, @file{.nncp.meta}} file.
@item Checks existence and size of every @file{.nncp.chunkXXX}.
@item Verifies integrity of every chunk.
@item Concatenates all chunks, simultaneously removing them from filesystem.
@end enumerate

That process reads the whole data twice. Be sure to have free disk
space for at least one chunk. Decrypted chunk files as a rule are saved
in pseudo-random order, so removing them during reassembly process will
likely lead to filesystem fragmentation. Reassembly process on
filesystems with deduplication capability should be rather lightweight.

If @option{-dryrun} option is specified, then only existence and
integrity checking are performed.

If @option{-keep} option is specified, then no
@file{.nncp.meta}/@file{.nncp.chunkXXX} files are deleted during
reassembly process.

@option{-stdout} option outputs reassembled file to @code{stdout},
instead of saving to temporary file with renaming after. This could be
useful for reassembling on separate filesystem to lower fragmentation
effect, and/or separate storage device for higher performance.

@option{-dump} option prints meta-file contents in human-friendly form.
It is useful mainly for debugging purposes. For example:
@example
Original filename: testfile
File size: 3.8 MiB (3987795 bytes)
Chunk size: 1.0 MiB (1048576 bytes)
Number of chunks: 4
Checksums:
    0: eac60d819edf40b8ecdacd0b9a5a8c62de2d15eef3c8ca719eafa0be9b894017
    1: 013a07e659f2e353d0e4339c3375c96c7fffaa2fa00875635f440bbc4631052a
    2: f4f883975a663f2252328707a30e71b2678f933b2f3103db8475b03293e4316e
    3: 0e9e229501bf0ca42d4aa07393d19406d40b179f3922a3986ef12b41019b45a3
@end example

Do not forget about @ref{ChunkedZFS, possible} ZFS deduplication issues.