diff --git a/README.md b/README.md
index bee7301..66a6a3b 100644
--- a/README.md
+++ b/README.md
@@ -22,7 +22,7 @@ and do not need to be memorized.
 
 ```$ pip install magic-wormhole```
 
-On Debian/Ubuntu systems, you may first need `apt-get python-dev
+On Debian/Ubuntu systems, you may first need `apt-get install python-dev
 libffi-dev build-essential`. On Fedora it's `libffi-devel` and
 `python-devel`. On OS-X, you may need to install `pip` and run
 `xcode-select --install` to get GCC. Note: on Windows, only python2 is