如何使用Wget恢复部分下载的文件

前几天我在Arch Linux Linux桌面上测试FreeTube，一个开源的YouTube桌面播放器。我尝试使用“wget”命令从GitHub下载最新版本的FreeTube。由于我的土豆互联网连接，下载过程每隔几分钟就停止工作。这是我用来下载该文件的wget命令。

$ wget https://github.com/FreeTubeApp/FreeTube/releases/download/v0.1.3-beta/FreeTube-linux-x64.tar.xz

如下:

--2018-03-09 15:41:44-- https://github.com/FreeTubeApp/FreeTube/releases/download/v0.1.3-beta/FreeTube-linux-x64.tar.xz
Loaded CA certificate '/etc/ssl/certs/ca-certificates.crt'
Resolving github.com (github.com)... 192.30.253.113, 192.30.253.112, 64:ff9b::c01e:fd70, ...
Connecting to github.com (github.com)|192.30.253.113|:443... connected.
HTTP request sent, awaiting response... 302 Found
Location: https://github-production-release-asset-2e65be.s3.amazonaws.com/123220152/39a2c92c-2277-11e8-8ca4-895487b6ddb0?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIWNJYAX4CSVEH53A%2F20180309%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20180309T101016Z&X-Amz-Expires=300&X-Amz-Signature=bf0fcb4643f0719239e3a006c9fbc055b6b9805e6ef03dcfc27334d18fdf994c&X-Amz-SignedHeaders=host&actor_id=0&response-content-disposition=attachment%3B%20filename%3DFreeTube-linux-x64.tar.xz&response-content-type=application%2Foctet-stream [following]
--2018-03-09 15:41:47-- https://github-production-release-asset-2e65be.s3.amazonaws.com/123220152/39a2c92c-2277-11e8-8ca4-895487b6ddb0?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIWNJYAX4CSVEH53A%2F20180309%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20180309T101016Z&X-Amz-Expires=300&X-Amz-Signature=bf0fcb4643f0719239e3a006c9fbc055b6b9805e6ef03dcfc27334d18fdf994c&X-Amz-SignedHeaders=host&actor_id=0&response-content-disposition=attachment%3B%20filename%3DFreeTube-linux-x64.tar.xz&response-content-type=application%2Foctet-stream
Resolving github-production-release-asset-2e65be.s3.amazonaws.com (github-production-release-asset-2e65be.s3.amazonaws.com)... 52.216.225.200, 64:ff9b::34d8:e1c8
Connecting to github-production-release-asset-2e65be.s3.amazonaws.com (github-production-release-asset-2e65be.s3.amazonaws.com)|52.216.225.200|:443... connected.
HTTP request sent, awaiting response... 206 Partial Content
Length: 39318740 (37M), 24626833 (23M) remaining [application/octet-stream]
Saving to: ‘FreeTube-linux-x64.tar.xz’

FreeTube-linux-x64. 48%[+++++++=> ] 18.04M 4.63KB/s in 3m 6s

2018-03-09 15:49:59 (22.2 KB/s) - Read error at byte 18921544/39318740 (Error in the pull function.). Retrying.

--2018-03-09 15:50:00-- (try: 2) https://github-production-release-asset-2e65be.s3.amazonaws.com/123220152/39a2c92c-2277-11e8-8ca4-895487b6ddb0?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIWNJYAX4CSVEH53A%2F20180309%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20180309T101016Z&X-Amz-Expires=300&X-Amz-Signature=bf0fcb4643f0719239e3a006c9fbc055b6b9805e6ef03dcfc27334d18fdf994c&X-Amz-SignedHeaders=host&actor_id=0&response-content-disposition=attachment%3B%20filename%3DFreeTube-linux-x64.tar.xz&response-content-type=application%2Foctet-stream
Connecting to github-production-release-asset-2e65be.s3.amazonaws.com (github-production-release-asset-2e65be.s3.amazonaws.com)|52.216.225.200|:443... connected.
HTTP request sent, awaiting response... 403 Forbidden
2018-03-09 15:50:04 ERROR 403: Forbidden.

我检查了下载文件大小。

$ ls -lh FreeTube-linux-x64.tar.xz 
-rw-r--r-- 1 sk users 19M Mar 9 15:44 FreeTube-linux-x64.tar.xz

好吧，FreeTube的实际大小约为38MB，但到目前为止我只有19M。我重新运行Wget命令，希望它能恢复部分下载的文件，但事实并非如此。Wget从一开始就开始下载文件，几分钟后我得到了同样的错误。无论我尝试下载多少次，下载任务都会在几分钟后中断。

使用Wget恢复部分下载的文件

经过几次谷歌搜索并浏览wget手册页后，我发现有一个选项可以使用wget命令恢复部分下载的文件。

要恢复部分下载的文件，请转到存在部分下载文件的位置，并使用“-c”或“-continue”选项和wget命令一样使用，如下所示。

$ wget -c https://github.com/FreeTubeApp/FreeTube/releases/download/v0.1.3-beta/FreeTube-linux-x64.tar.xz

或者,

$ wget --continue https://github.com/FreeTubeApp/FreeTube/releases/download/v0.1.3-beta/FreeTube-linux-x64.tar.xz

现在，Wget开始从之前尝试的位置下载文件。“-c”或“ - continue”选项将继续获取部分下载的文件。当您想要完成由上一个Wget实例或其他程序启动的下载时，这将非常有用。

请注意，如果当前目录中存在具有相同名称的文件，Wget将假定它是远程文件的第一部分，并将要求服务器从等于本地长度的偏移量继续检索文件。因此，只需确保删除了所有其他部分下载的文件，并保留您要下载的原始文件。

有关更多详细信息，请参阅手册页。

$ man wget

或者,

$ wget --help