TranslateProject/published/201701/20170104 Speed up your downloads with Axel command line downloader.md

使用 Axel 命令行下载器/加速器加速下载

Axel 是一个轻量级下载程序，它和其他加速器一样，对同一个文件建立多个连接，每个连接下载单独的文件片段以更快地完成下载。

Axel 支持 HTTP、HTTPS、FTP 和 FTPS 协议。它也可以使用多个镜像站点下载单个文件，所以，Axel 可以加速下载高达 40％（大约，我个人认为）。它非常轻量级，因为它没有依赖并且使用非常少的 CPU 和内存。

Axel 一步到位地将所有数据直接下载到目标文件（LCTT 译注：而不是像其它的下载软件那样下载成多个文件块，然后拼接）。

注意：不支持在单条命令中下载两个文件。

你还可以尝试其他命令行下载管理器/加速器。

• [aria2 - 超快速下载程序] 1
• [wget - 标准命令行下载程序] 2
• [curl - 命令行下载程序] 3
• [Linux 下的最好的 4 个命令行下载管理器/加速器] 4

大多数发行版（Debian、Ubuntu、Mint、Fedora、suse、openSUSE、Arch Linux、Manjaro、Mageia 等）都有 axel 包，所以我们可以从发行版官方仓库轻松安装。对于 CentOS/RHEL，我们需要启用 EPEL Repository。

[在 Debian/Ubuntu/LinuxMint 上安装 Axel]
$ sudo apt-get install axel

[在 RHEL/CentOS 上安装 Axel]
$ sudo yum install axel

[在 Fedora 上安装 Axel]
$ sudo dnf install axel

[在 openSUSE 上安装 Axel]
$ sudo zypper install axel

[在 Mageia 上安装 Axel]
$ sudo urpmi axel

[在基于 Arch Linux 的发行版安装 Axel]
$ sudo pacman -S axel

1) 下载单个文件

以下命令将从给定的 URL 下载文件并存储在当前目录中，下载文件时，我们可以看到文件的信息（建立的连接数、下载速度、下载进度、完成下载所花费的时间以及连接完成的时间）。

# axel https://download.owncloud.org/community/owncloud-9.0.0.tar.bz2
Initializing download: https://download.owncloud.org/community/owncloud-9.0.0.tar.bz2
File size: 22678208 bytes
Opening output file owncloud-9.0.0.tar.bz2
Starting download

[  0%]  .......... .......... .......... .......... ..........  [ 146.7KB/s]
[  0%]  .......... .......... .......... .......... ..........  [ 267.0KB/s]
[  0%]  .......... .......... .......... .......... ..........  [ 373.9KB/s]
[  0%]  .......... .......... .......... .......... ..........  [ 406.9KB/s]
[  0%]  .......... .......... .......... .......... ..........  [ 487.5KB/s]
[  1%]  .......... .......... .......... .......... ..........  [ 572.6KB/s]
[  1%]  .......... .......... .......... .......... ..........  [ 650.7KB/s]
[  1%]  .......... .......... .......... .......... ..........  [ 649.3KB/s]
[  1%]  .......... .......... .......... .......... ..........  [ 718.1KB/s]
[  2%]  .......... .......... .......... .......... ..........  [ 769.3KB/s]
[  2%]  .......... .......... .......... .......... ..........  [ 838.7KB/s]
[  2%]  .......... .......... .......... .......... ..........  [ 866.0KB/s]
Connection 0 finished
.
.
[ 99%]  .......... .......... .......... .......... ..........  [5721.0KB/s]
Connection 2 finished
[ 99%]  .......... .......... .......... .......... ..........  [5733.4KB/s]
Connection 1 finished
[ 99%]  .......... .......... .......... .......... ..........  [5745.4KB/s]
[100%]  .......... .......... .......... .......... ......

Downloaded 21.6 megabytes in 3 seconds. (5755.94 KB/s)

2) 用不同的名称保存文件

要使用其他名称来保存文件，启动下载时可以添加 -o（小写字母）选项和文件名。这里我们使用文件名 owncloud.tar.bz2 来保存文件。

# axel -o cloud.tar.bz2 https://download.owncloud.org/community/owncloud-9.0.0.tar.bz2
Initializing download: https://download.owncloud.org/community/owncloud-9.0.0.tar.bz2
File size: 22678208 bytes
Opening output file cloud.tar.bz2
Starting download

[  0%]  .......... .......... .......... .......... ..........  [ 143.0KB/s]
[  0%]  .......... .......... .......... .......... ..........  [ 264.1KB/s]
[  0%]  .......... .......... .......... .......... ..........  [ 309.8KB/s]
[  0%]  .......... .......... .......... .......... ..........  [ 406.3KB/s]
[  0%]  .......... .......... .......... .......... ..........  [ 495.4KB/s]
[  1%]  .......... .......... .......... .......... ..........  [ 586.3KB/s]
[  1%]  .......... .......... .......... .......... ..........  [ 673.1KB/s]
[  1%]  .......... .......... .......... .......... ..........  [ 647.1KB/s]
[  1%]  .......... .......... .......... .......... ..........  [ 721.1KB/s]
[  2%]  .......... .......... .......... .......... ..........  [ 781.3KB/s]
Connection 2 finished
.
.
Connection 0 finished
[ 98%]  .......... .......... .......... .......... ..........  [6221.9KB/s]
[ 98%]  .......... .......... .....
Connection 1 finished
        ,,,,,,,,,, ,,,,,,,,,, ,,,,,..... .......... ..........  [6145.6KB/s]
[ 99%]  .......... .......... .......... .......... ..........  [6159.2KB/s]
[ 99%]  .......... .......... .......... .......... ..........  [6172.0KB/s]
[ 99%]  .......... .......... .......... .......... ..........  [5977.9KB/s]
[ 99%]  .......... .......... .......... .......... ..........  [5989.6KB/s]
[100%]  .......... .......... .......... .......... ......

Downloaded 21.6 megabytes in 3 seconds. (6001.05 KB/s)

3) 限制下载速度

默认情况下 axel 以字节/秒为单位设置下载文件的最大速度。当我们的网络连接速度较慢时，可以使用此选项。只需添加 -s 选项，后面跟字节值。这里我们要限速 512 KB/s 下载一个文件。

# axel -s 512000 https://download.owncloud.org/community/owncloud-9.0.0.tar.bz2
Initializing download: https://download.owncloud.org/community/owncloud-9.0.0.tar.bz2
File size: 22678208 bytes
Opening output file owncloud-9.0.0.tar.bz2
Starting download

[  0%]  .......... .......... .......... .......... ..........  [ 141.5KB/s]
[  0%]  .......... .......... .......... .......... ..........  [ 266.1KB/s]
[  0%]  .......... .......... .......... .......... ..........  [ 308.0KB/s]
[  0%]  .......... .......... .......... .......... ..........  [ 405.9KB/s]
[  0%]  .......... .......... .......... .......... ..........  [ 496.7KB/s]
[  1%]  .......... .......... .......... .......... ..........  [ 526.4KB/s]
[  1%]  .......... .......... .......... .......... ..........  [ 507.0KB/s]
[  1%]  .......... .......... .......... .......... ..........  [ 505.6KB/s]
[  1%]  .......... .......... .......... .......... ..........  [ 504.8KB/s]
[  2%]  .......... .......... .......... .......... ..........  [ 503.9KB/s]
[  2%]  .......... .......... .......... .......... ..........  [ 503.4KB/s]
.
.
[ 99%]  .......... .......... .......... .......... ..........  [ 497.0KB/s]
[ 99%]  .......... .......... .......... .......... ..........  [ 496.9KB/s]
[100%]  .......... ..
Connection 0 finished
        ,,,,,,,,,, ,,.....
Connection 1 finished
Connection 3 finished
        ,,,,,,,,,, ,,,,,,,... .......... .......... ......

Downloaded 21.6 megabytes in 44 seconds. (494.54 KB/s)

4) 限制连接数

axel 默认建立 4 个连接以从不同的镜像获取文件。此外，我们可以通过使用 -n 选项添加更多的连接，后跟连接数 10 来提高下载速度。保险起见，我们添加了十个连接，但不幸的是，它花了更多时间来下载文件。

# axel -n 10 https://download.owncloud.org/community/owncloud-9.0.0.tar.bz2
Initializing download: https://download.owncloud.org/community/owncloud-9.0.0.tar.bz2
File size: 22678208 bytes
Opening output file owncloud-9.0.0.tar.bz2
Starting download

[  0%]  .......... .......... .......... .......... ..........  [ 140.8KB/s]
[  0%]  .......... .......... .......... .......... ..........  [ 265.7KB/s]
[  0%]  .......... .......... .......... .......... ..........  [ 305.4KB/s]
[  0%]  .......... .......... .......... .......... ..........  [ 402.1KB/s]
[  0%]  .......... .......... .......... .......... ..........  [ 496.3KB/s]
[  1%]  .......... .......... .......... .......... ..........  [ 522.1KB/s]
[  1%]  .......... .......... .......... .......... ..........  [ 567.5KB/s]
[  1%]  .......... .......... .......... .......... ..........  [ 640.5KB/s]
[  1%]  .......... .......... .......... .......... ..........  [ 710.8KB/s]
[  2%]  .......... .......... .......... .......... ..........  [ 780.5KB/s]
.
.
[ 98%]  .......... .......... .......... .......... ..........  [7544.9KB/s]
[ 98%]  .......... .......... .......... .......... ..........  [7557.9KB/s]
[ 98%]  .......... .......... .......... .......... ..........  [7570.4KB/s]
[ 98%]  .......... .......... .......... .......... ..........  [7495.3KB/s]
[ 99%]  .......... .......... .......... .......... ......
Connection 2 finished
        ,,,,,,,,,, ,,,,,,,,,, ,,,,,,,,,, ,,,,,,,,,, ,,,,,,....  [7311.6KB/s]
[ 99%]  .......... .......... .......... .......... ..........  [7318.9KB/s]
[ 99%]  .......... .......... .......... .......... ..........
Connection 9 finished
        ,,,,,,,,,, ,,,,,,,,,, ,,,,,,,,,, ,,,,,,,,,, ,,,,,,,,,,  [7331.0KB/s]
[ 99%]  .......... .......... .......... ..........
Connection 3 finished
        ,,,,,,,,,, ,,,,,,,,,, ,,,,,,,,,, ,,,,,,,,,, ..........  [4300.7KB/s]
[100%]  .......... .......... .......... .......... ......

Downloaded 21.6 megabytes in 5 seconds. (4109.41 KB/s)

5) 恢复未完成的下载

axel 默认具有恢复未完成的下载的行为。Axel 在下载文件时定期更新状态文件（扩展名为 .st）。由于某些原因，下载中途停止了？不用担心，只要使用相同的 axel 命令，它将会检查 file 和 file.st，如果找到，它会从停止处恢复下载。

# axel https://download.owncloud.org/community/owncloud-9.0.0.tar.bz2
Initializing download: https://download.owncloud.org/community/owncloud-9.0.0.tar.bz2
File size: 22678208 bytes
Opening output file owncloud-9.0.0.tar.bz2
Starting download

[  0%]  .......... .......... .......... .......... ..........  [ 140.8KB/s]
[  0%]  .......... .......... .......... .......... ..........  [ 265.7KB/s]
[  0%]  .......... .......... .......... .......... ..........  [ 305.4KB/s]
[  0%]  .......... .......... .......... .......... ..........  [ 402.1KB/s]
[  0%]  .......... .......... .......... .......... ..........  [ 496.3KB/s]
[  1%]  .......... .......... .......... .......... ..........  [ 522.1KB/s]
[  1%]  .......... .......... .......... .......... ..........  [ 567.5KB/s]
[  1%]  .......... .......... .......... .......... ..........  [ 640.5KB/s]
[  1%]  .......... .......... .......... .......... ..........  [ 710.8KB/s]
[  2%]  .......... .......... .......... .......... ..........  [ 780.5KB/s]
.
.
[ 84%]  .......... .......... .......... .......... ..........  [7100.7KB/s]
[ 84%]  .......... .......... .......... .......... ..........  [7104.3KB/s]
[ 84%]  .......... .......... .......... .^C

Downloaded 18.3 megabytes in 2 seconds. (7009.79 KB/s)

上面的输出清晰地显示了在下载断开时有两个文件 owncloud-9.0.0.tar.bz2 和 owncloud-9.0.0.tar.bz2.st。当重新开始下载时，它会从停止处开始下载。

# ls -lh
total 19M
-rw------- 1 root root 22M Dec 27 08:33 owncloud-9.0.0.tar.bz2
-rw------- 1 root root  44 Dec 27 08:33 owncloud-9.0.0.tar.bz2.st

# axel https://download.owncloud.org/community/owncloud-9.0.0.tar.bz2
Initializing download: https://download.owncloud.org/community/owncloud-9.0.0.tar.bz2
File size: 22678208 bytes
Opening output file owncloud-9.0.0.tar.bz2
State file found: 19180828 bytes downloaded, 3497380 to go.
Starting download

        ,,,,,,,,,, ,,,,,,,,,, ,,,,,,,,,, ,......... ..........  [  66.5KB/s]
[ 84%]  .......... .......... .......... .......... ..........  [ 186.0KB/s]
[ 85%]  .......... .......... .......... .......... ..........  [ 241.7KB/s]
[ 85%]  .......... .......... .......... .......... ..........  [ 335.6KB/s]
[ 85%]  .......... .......... .......... .......... ..........  [ 351.5KB/s]
[ 85%]  .......... .......... .......... .......... ..........  [ 427.1KB/s]
[ 85%]  .......... .......... .......... .......... ..........  [ 427.4KB/s]
[ 86%]  .......... .......... .......... .......... ..........  [ 491.5KB/s]
.
.
[ 98%]  ...
Connection 0 finished
        ,,,....... .......... .......... .......... ..........  [2106.6KB/s]
[ 99%]  .......... .......... .......... .......... ..........  [2140.5KB/s]
[ 99%]  .......... .......... .......... .......... ..........  [2172.4KB/s]
[ 99%]  .......... .......... .......... .......... ..........  [2203.2KB/s]
[ 99%]  .......... .......... .......... .......... ..........  [2236.2KB/s]
[100%]  .......... .......... .......... .......... ......

Downloaded 3415.4 kilobytes in 1 second. (2264.93 KB/s)

6) 不显示文件下载进度

如果你不想要看到文件的下载进度，只要在 axel 命令中加入 -q 选项。

# axel -q https://download.owncloud.org/community/owncloud-9.0.0.tar.bz2

7) 替换进度条

如果你不喜欢默认的进度条，你可以使用 -a 选项来替换进度条。

# axel -a https://download.owncloud.org/community/owncloud-9.0.0.tar.bz2
Initializing download: https://download.owncloud.org/community/owncloud-9.0.0.tar.bz2
File size: 22678208 bytes
Opening output file owncloud-9.0.0.tar.bz2
Starting download

[ 66%] [......0      ...1        ..........2  ...........3] [   5.8MB/s] [00:01]^C

Downloaded 14.3 megabytes in 2 seconds. (5916.11 KB/s)

我们中断了上面的下载，以便在下载文件时能清楚地显示替代进度条状态。一旦文件成功下载后，你可以看到相同的输出，如下所示。

# axel -a https://download.owncloud.org/community/owncloud-9.0.0.tar.bz2
File size: 22678208 bytes
Opening output file owncloud-9.0.0.tar.bz2
Starting download

Connection 2 finished                                                          ]
Connection 1 finished                                                          ]
Connection 3 finished                                                          ]
Connection 0 finished                                                          ]

Downloaded 21.6 megabytes in 4 seconds. (5062.32 KB/s)

8) 了解关于 axel 的更多信息

如果你想要了解更多关于 axel 的选项，只需要进入它的手册。

# man axel
或者
# axel --help

享受吧。。。)

---

via: http://www.2daygeek.com/axel-command-line-downloader-accelerator-for-linux/

作者：Magesh Maruthamuthu 译者：geekpi 校对：jasminepeng

本文由 LCTT 原创编译，Linux中国 荣誉推出