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+# Fast File Downloader
+A simple CLI application to download files over HTTP with the goal of maximum throuput by parallelizing downloads. Optimized for downloading large quantities of files from [zippyshare](https://zippyshare.com/) as fast as possible. 
+
+## Features
+* Automatically download files from a URL list
+* Automatically fetch actual download URLs for [zippyshare](https://zippyshare.com/) and [sendcm](https://send.cm/) links
+* Download multiple files at the same time
+* Use multiple connections to download non overlapping chunks of the same file in parallel
+  * This can be used to gain more download speed than a server would normally provide to a single connection
+  * Works really well with zippyshare
+  * This requires high random write performance for the local storage and will bottleneck on HDDs
+  * Only works if the host supports the HTTP Range header and doesn't otherwise block it
+
+## Performance
+On a 1000Mbit connection (actual speed ~800Mbit) I can download with about 90MB/s through a wireguard VPN from zippyshare when using 5 files in parallel with 10 connections each (`-n 5 -c 10`). 
+
+When downloading the same content manually through a browser I get about 5MB/s per file, dropping to 0.5-1MB/s after a few seconds. Also I of course have to start all the downloads by hand which is quite annoying.
+
+## Usage
+Simply create a textfile and enter the URLs one per line. Comments using `#` and empty lines are allowed.
+
+```
+$ cat list.txt
+# My encrypted documents backup
+https://www71.zippyshare.com/v/XXXXXXX/file.html
+https://www72.zippyshare.com/v/XXXXYYY/file.html
+https://www73.zippyshare.com/v/XXXXZZZ/file.html
+https://www74.zippyshare.com/v/Xagdgfh/file.html
+
+# My encrypted video backup
+https://www75.zippyshare.com/v/sdsgfds/file.html
+https://www76.zippyshare.com/v/dfsdxfd/file.html
+https://www75.zippyshare.com/v/dsgsdgf/file.html
+https://www76.zippyshare.com/v/drtdrtd/file.html
+https://www75.zippyshare.com/v/erdfghd/file.html
+https://www76.zippyshare.com/v/87654rd/file.html
+https://www75.zippyshare.com/v/dfghdfg/file.html
+https://www76.zippyshare.com/v/hkjghjk/file.html
+```
+
+And then download the files using the desired levels of concurrency (e.g. 5 files at once with 10 connections each):
+```
+$ ffdl -l list.txt -o ~/Downloads/ -c 10 -n 5
+```
+
+## CLI Arguments
+
+```
+$ ffdl --help
+
+FFDL - Fast File Downloader 0.1.2
+Download files fast
+
+USAGE:
+    ffdl.exe [OPTIONS]
+
+OPTIONS:
+    -c, --connections <CONNECTIONS PER FILE>
+            The number concurrent connections per file download. Increasing this number will
+            increase the download speed of individual files if supported by the server but setting
+            this number too high may cause the download to fail.
+            NOTE: This mode will write cause random writes and for that reason won't work on HDDs.
+            WARNING: Files started with multiple connections currently can't be continued. [default:
+            1]
+
+    -d, --download <URL>
+            Download only the one file from the specified url
+
+    -h, --help
+            Print help information
+
+    -l, --listfile <URL LISTFILE>
+            Download all files from the specified url list file
+
+    -n, --num-files <PARALLEL DOWNLOADS>
+            Specify the number of files from that should be downloaded in parallel. Increasing this
+            number will increase the total download speed but won't improve the download speed for
+            individual files [default: 1]
+
+    -o, --outdir <OUTPUT DIR>
+            Set the output directory in which the downloads will be stored. The directory will be
+            created if it doesn't exit yet [default: ./]
+
+    -V, --version
+            Print version information
+```