Fix my bad bash

Author: benhylau

README.md

@@ -62,7 +62,7 @@ If you want to generate course assets yourself, simply run `./install-dependenci
 
 ## Credits
 
-The first version of this syllabus is created by [Toronto Mesh](https://tomesh.net) contributors: [@benhylau](https://github.com/benhylau), [@darkdrgn2k](https://github.com/darkdrgn2k), [@dcwalk](https://github.com/dcwalk), [@uditvira](https://github.com/uditvira), [@Shrinks99](https://github.com/Shrinks99), and [@Pedro-on-a-bike](https://github.com/Pedro-on-a-bike). While most of the material is created new, the course also incorporates many prior works listed [here]({{ site.baseurl }}/articles/general/general-extra-resources.pdf), or otherwise reference in their individual course modules.
+The first version of this syllabus is created by [Toronto Mesh](https://tomesh.net) contributors: [@benhylau](https://github.com/benhylau), [@darkdrgn2k](https://github.com/darkdrgn2k), [@dcwalk](https://github.com/dcwalk), [@uditvira](https://github.com/uditvira), [@Shrinks99](https://github.com/Shrinks99), and [@Pedro-on-a-bike](https://github.com/Pedro-on-a-bike). While most of the material is created new, the course also incorporates many prior works listed [here]({{ site.baseurl }}/articles/general/general-extra-resources.pdf), or otherwise referenced in their individual course modules.
 
 Hands-on activities rely on software from many projects: [mesh-orange](https://github.com/tomeshnet/mesh-orange), [mesh-router-builder](https://github.com/benhylau/mesh-router-builder), [mesh-workshop](https://github.com/benhylau/mesh-workshop/), [steamlink](https://github.com/steamlink), [cjdns](https://github.com/cjdelisle/cjdns/), [Yggdrasil](https://yggdrasil-network.github.io/about.html), [IPFS](https://ipfs.io/), [Secure Scuttlebutt](https://github.com/ssbc/). Course material generation uses [markdown-pdf](https://github.com/alanshaw/markdown-pdf) and [gitbook-cli](https://github.com/GitbookIO/gitbook-cli). The course website is built with [Jekyll](https://jekyllrb.com/), and the theme is from [Mozilla's Open Leadership Training Series](https://github.com/mozilla/open-leadership-training-series). Icons from [Font Awesome](http://fontawesome.io/) and [Jake Ingman](https://thenounproject.com/search/?q=mesh&i=74809) are used.
 

package.sh

@@ -97,7 +97,7 @@ for mod in module-*; do
     filename="$mod.pdf"
     echo "* [$filename]($filename)" >> "$dst/pdf-assets.md"
 
-    if [ -f "output/$mod/worksheet/*.pdf" ]; then
+    if [ -d output/$mod/worksheet ] && [ "$(ls output/$mod/worksheet/*.pdf 2>/dev/null)" ]; then
         echo "" >> "$dst/pdf-assets.md"
         echo "### Class worksheets" >> "$dst/pdf-assets.md"
         for doc in output/$mod/worksheet/*.pdf; do