Ubuntu – How to extract all PDF links on a website

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This is a little off topic, but I hope you guys will help me. I've found a website full of articles I need, but those are mixed with a lot of useless files (mainly jpgs).

I would like to know if there is a way to find (not download) all PDFs on the server to make a list of links. Basically I would simply like to filter out everything that's not a PDF, in order to get a better view on what to download and what not.

Best Answer

Overview

Ok, here you go. This is a programmatic solution in form of a script:

#!/bin/bash

# NAME:         pdflinkextractor
# AUTHOR:       Glutanimate (http://askubuntu.com/users/81372/), 2013
# LICENSE:      GNU GPL v2
# DEPENDENCIES: wget lynx
# DESCRIPTION:  extracts PDF links from websites and dumps them to the stdout and as a textfile
#               only works for links pointing to files with the ".pdf" extension
#
# USAGE:        pdflinkextractor "www.website.com"

WEBSITE="$1"

echo "Getting link list..."

lynx -cache=0 -dump -listonly "$WEBSITE" | grep ".*\.pdf$" | awk '{print $2}' | tee pdflinks.txt

# OPTIONAL
#
# DOWNLOAD PDF FILES
#
#echo "Downloading..."    
#wget -P pdflinkextractor_files/ -i pdflinks.txt

Installation

You will need to have wget and lynx installed:

sudo apt-get install wget lynx

Usage

The script will get a list of all the .pdf files on the website and dump it to the command line output and to a textfile in the working directory. If you comment out the "optional" wget command the script will proceed to download all files to a new directory.

Example

$ ./pdflinkextractor http://www.pdfscripting.com/public/Free-Sample-PDF-Files-with-scripts.cfm
Getting link list...
http://www.pdfscripting.com/public/FreeStuff/PDFSamples/JSPopupCalendar.pdf
http://www.pdfscripting.com/public/FreeStuff/PDFSamples/ModifySubmit_Example.pdf
http://www.pdfscripting.com/public/FreeStuff/PDFSamples/DynamicEmail_XFAForm_V2.pdf
http://www.pdfscripting.com/public/FreeStuff/PDFSamples/AcquireMenuItemNames.pdf
http://www.pdfscripting.com/public/FreeStuff/PDFSamples/BouncingButton.pdf
http://www.pdfscripting.com/public/FreeStuff/PDFSamples/JavaScriptClock.pdf
http://www.pdfscripting.com/public/FreeStuff/PDFSamples/Matrix2DOperations.pdf
http://www.pdfscripting.com/public/FreeStuff/PDFSamples/RobotArm_3Ddemo2.pdf
http://www.pdfscripting.com/public/FreeStuff/PDFSamples/SimpleFormCalculations.pdf
http://www.pdfscripting.com/public/FreeStuff/PDFSamples/TheFlyv3_EN4Rdr.pdf
http://www.pdfscripting.com/public/FreeStuff/PDFSamples/ImExportAttachSample.pdf
http://www.pdfscripting.com/public/FreeStuff/PDFSamples/AcroForm_BasicToggle.pdf
http://www.pdfscripting.com/public/FreeStuff/PDFSamples/AcroForm_ToggleButton_Sample.pdf
http://www.pdfscripting.com/public/FreeStuff/PDFSamples/AcorXFA_BasicToggle.pdf
http://www.pdfscripting.com/public/FreeStuff/PDFSamples/ConditionalCalcScripts.pdf
Downloading...
--2013-12-24 13:31:25--  http://www.pdfscripting.com/public/FreeStuff/PDFSamples/JSPopupCalendar.pdf
Resolving www.pdfscripting.com (www.pdfscripting.com)... 74.200.211.194
Connecting to www.pdfscripting.com (www.pdfscripting.com)|74.200.211.194|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 176008 (172K) [application/pdf]
Saving to: `/Downloads/pdflinkextractor_files/JSPopupCalendar.pdf'

100%[===========================================================================================================================================================================>] 176.008      120K/s   in 1,4s    

2013-12-24 13:31:29 (120 KB/s) - `/Downloads/pdflinkextractor_files/JSPopupCalendar.pdf' saved [176008/176008]

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