Added guard closes and some docs to download script. Added it to scripts folder. Added download script readme. Added section in root readme.

README.md

@@ -119,6 +119,14 @@ Reading a paper is not the same as reading a blogpost or a novel. Here are a few
 
 * Love a Paper - [@loveapaper](https://twitter.com/loveapaper)
 
+### Download all papers
+
+Open your favourite terminal and run:
+
+```bash
+$ ./scripts/download_all.sh
+```
+
 ## Contributing Guidelines
 
 Please take a look at our [CONTRIBUTING.md](https://github.com/papers-we-love/papers-we-love/blob/master/.github/CONTRIBUTING.md) file.

scripts/README.md

@@ -0,0 +1,12 @@
+# Download Utility
+
+A nice little script to download all papers (pdfs) in the repo to their respective folders.
+
+### Usage
+Simply open a terminal and run:
+
+```bash
+$ ./download_all.sh
+```
+
+This can be run from anywhere as long as the script doesn't change location

scripts/download_all.sh

@@ -0,0 +1,29 @@
+#!/bin/bash
+
+# Guard clause check if required binaries are installed
+which wget > /dev/null || { echo "Error: wget not installed." ; exit 1 ; }
+which egrep > /dev/null || { echo "Error: egrep not installed." ; exit 1 ; }
+which xargs > /dev/null || { echo "Error: xargs not installed." ; exit 1 ; }
+
+# Recursively traverse directories in repo scraping markdown file for URLs
+# containing pdfs. Downloads pdfs into respective directories.
+download_for_directory() {
+    cd $1
+    for f in *; do
+        if [ -d "$f" ]; then
+            download_for_directory $f &
+        fi
+    done
+
+    ls | cat *.md 2> /dev/null \
+    | egrep -o 'https?://[^ ]+' \
+    | grep 'pdf' | tr -d ')' \
+    | xargs --no-run-if-empty wget --no-clobber --quiet --timeout=5 --tries=2
+    
+    cd ..
+    echo "$1 done."
+}
+
+BASEDIR="$(dirname $0)/.."
+download_for_directory $BASEDIR
+wait