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emphasize usage of -r in documentation

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notably as a way to overcome shell expansion limitations,
notably in a scenario of dictionary training.
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Yann Collet 2021-09-22 14:00:20 -07:00
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@ -224,7 +224,11 @@ the last one takes effect.
keep source file(s) after successful compression or decompression. keep source file(s) after successful compression or decompression.
This is the default behavior. This is the default behavior.
* `-r`: * `-r`:
operate recursively on directories operate recursively on directories.
It selects all files in the named directory and all its subdirectories.
This can be useful both to reduce command line typing,
and to circumvent shell expansion limitations,
when there are a lot of files and naming breaks the maximum size of a command line.
* `--filelist FILE` * `--filelist FILE`
read a list of files to process as content from `FILE`. read a list of files to process as content from `FILE`.
Format is compatible with `ls` output, with one file per line. Format is compatible with `ls` output, with one file per line.
@ -307,12 +311,14 @@ Compression of small files similar to the sample set will be greatly improved.
The training set should contain a lot of small files (> 100), The training set should contain a lot of small files (> 100),
and weight typically 100x the target dictionary size and weight typically 100x the target dictionary size
(for example, 10 MB for a 100 KB dictionary). (for example, 10 MB for a 100 KB dictionary).
`--train` can be combined with `-r` to indicate a directory rather than listing all the files,
which can be useful to circumvent shell expansion limits.
Supports multithreading if `zstd` is compiled with threading support. `--train` supports multithreading if `zstd` is compiled with threading support (default).
Additional parameters can be specified with `--train-fastcover`. Additional parameters can be specified with `--train-fastcover`.
The legacy dictionary builder can be accessed with `--train-legacy`. The legacy dictionary builder can be accessed with `--train-legacy`.
The cover dictionary builder can be accessed with `--train-cover`. The slower cover dictionary builder can be accessed with `--train-cover`.
Equivalent to `--train-fastcover=d=8,steps=4`. Default is equivalent to `--train-fastcover=d=8,steps=4`.
* `-o file`: * `-o file`:
Dictionary saved into `file` (default name: dictionary). Dictionary saved into `file` (default name: dictionary).
* `--maxdict=#`: * `--maxdict=#`:
@ -322,10 +328,10 @@ Compression of small files similar to the sample set will be greatly improved.
Will generate statistics more tuned for selected compression level, Will generate statistics more tuned for selected compression level,
resulting in a _small_ compression ratio improvement for this level. resulting in a _small_ compression ratio improvement for this level.
* `-B#`: * `-B#`:
Split input files in blocks of size # (default: no split) Split input files into blocks of size # (default: no split)
* `--dictID=#`: * `--dictID=#`:
A dictionary ID is a locally unique ID that a decoder can use to verify it is A dictionary ID is a locally unique ID
using the right dictionary. that a decoder can use to verify it is using the right dictionary.
By default, zstd will create a 4-bytes random number ID. By default, zstd will create a 4-bytes random number ID.
It's possible to give a precise number instead. It's possible to give a precise number instead.
Short numbers have an advantage : an ID < 256 will only need 1 byte in the Short numbers have an advantage : an ID < 256 will only need 1 byte in the