qdownload2 功能和 qdownload 一致，选项也是一一对应，不过 qdownload2 通过命令行的方式来指定各个需要的参数，例如：
qshell qdownload2 --dest-dir=/home/jemy/temp --bucket=test
- 使用 bucket 绑定的源站域名和七牛源站域名下载资源，这部分下载产生的流量会生成存储源站下载流量的计费，请注意，这部分计费不在七牛 CDN 免费 10G 流量覆盖范围，具体域名使用参考 qdownload 命令的同功能配置：domain 。
Key中的/会被当做路径处理，也即任何以/结尾的Key均会被当做文件夹处理。- 如果使用的是 CDN 域名，且 CDN 域名开启了图片优化中的图片自动瘦身功能时，下载文件的信息和七牛服务端记录的文件信息不一致，此时下载不要使用 --check-size 和 --check-hash 选项，否则下载会失败。
其所支持的命令参数列表，可以通过 -h 选项获得，参数含义参考 qdownload 类似选项的含义：qdownload
例子：
qdownload2 的 --bucket 选项含义可参考 qdownload 的 bucket 配置；
qdownload2 的 --check-hash 选项含义可参考 qdownload 的 check_hash 配置；
qshell qdownload2 -h
Usage:
qshell qdownload2 [-c <ThreadCount>] [flags]
Flags:
--bucket string storage bucket
--check-hash whether to verify the hash, if it is enabled, it may take a long time
--check-size check the consistency of the file size between the local file and the server file. the download fails while the file is inconsistent.
--dest-dir string local storage path, full path. default current dir
--domain string domain of the download request, the default is empty, which means downloading from the storage source site
--enable-slice whether to enable slice download, you need to pay attention to the configuration of --slice-file-size-threshold slice threshold option. Only when slice download is enabled and the size of the downloaded file is greater than the slice threshold will the slice download be started
-e, --failure-list string specifies the file path where the failure file list is saved
--get-file-api public storage cloud not support, private storage cloud support when has getfile api.
-h, --help help for qdownload2
--io-host string io host of request
--key-file string configure a file and specify the keys to be downloaded; if not configured, download all the files in the bucket
--log-file string the output file of the download log is output to the file specified by record_root by default, and the specific file path can be seen in the terminal output
--log-level string download log output level, optional values are debug,info,warn and error (default "debug")
--log-rotate int the switching period of the download log file, the unit is day, (default 7)
--prefix string only download files with the specified prefix
--public whether the space is a public space
--record-root string path to save download record information, including log files and download progress files; the default is download directory
--referer string if the CDN domain name is configured with domain name whitelist anti-leech, you need to specify a referer address that allows access
--remove-temp-while-error when the download encounters an error, delete the previously downloaded part of the file cache
--save-path-handler string specify a callback function; when constructing the save path of the file, this option is preferred for construction. If not configured, $dest_dir + $ file separator + $Key will be used for construction. This function is implemented through the template of the Go language. The func command is used for function verification. For the specific syntax, please refer to the description of the func command.
--slice-concurrent-count int concurrency of slice downloads (default 10)
--slice-file-size-threshold int file threshold for downloading slices. When slice downloading is enabled and the file size is greater than this threshold, slice downloading will be enabled; unit:B (default 41943040)
--slice-size int slice size; when using slice download, the size of each slice; unit:B (default 4194304)
-s, --success-list string specifies the file path where the successful file list is saved
--suffixes string only download files with the specified suffixes
-c, --thread-count int num of threads to download files (default 5)