diff --git a/doc/BUILDING-external-libs.md b/doc/BUILDING-external-libs.md
index 87058dc9..af979a25 100644
--- a/doc/BUILDING-external-libs.md
+++ b/doc/BUILDING-external-libs.md
@@ -8,7 +8,7 @@ replacing "32" with "64".
 ## Prepare Ubuntu environment
 
 ```
-sudo apt-install build-essential cmake tofrodos
+sudo apt-get install build-essential cmake tofrodos
 sudo mkdir /opt/android
 sudo chown $LOGNAME /opt/android
 ```