diff --git a/README.md b/README.md
index 3cb52f3..547b5ca 100644
--- a/README.md
+++ b/README.md
@@ -54,12 +54,25 @@ If you wish to customize the command used to build the docs (defaults to
 example, to invoke sphinx-build directly you can use:
 
 ```yaml
+    - uses: ammaraskar/sphinx-action@master
       with:
         repo-token: "${{ secrets.GITHUB_TOKEN }}"
         build-command: "sphinx-build -b html . _build"
         args: "docs/"
 ```
 
+If there's system level dependencies that need to be installed for your
+build, you can use the `pre-build-command` argument like so:
+
+```yaml
+    - uses: ammaraskar/sphinx-action@master
+      with:
+        repo-token: "${{ secrets.GITHUB_TOKEN }}"
+        pre-build-command: "apt-get update -y && apt-get install -y latexmk texlive-latex-recommended texlive-latex-extra texlive-fonts-recommended"
+        build-command: "make latexpdf"
+        args: "docs2/"
+```
+
 ## Running the tests
 
 `python -m unittest`
diff --git a/action.yml b/action.yml
index 36ecfc8..c67b48c 100644
--- a/action.yml
+++ b/action.yml
@@ -24,7 +24,8 @@ inputs:
   pre-build-command:
     description:
       Run before the build command, you can use this to install system level
-      dependencies.
+      dependencies, for example with
+      "apt-get update -y && apt-get install -y perl"
     required: false
 runs:
   using: 'docker'