fix install instructions for linux

dopey · dopey · commit f28554d3142d · 2018-08-20T17:22:42.000-07:00
diff --git a/README.md b/README.md
@@ -57,7 +57,7 @@ wget https://github.com/smallstep/cli/releases/download/X.Y.Z/step_X.Y.Z_amd64.d
 Install the Debian package:
 
 ```
-sudo dpkg -s step_X.Y.Z_amd64.deb
+sudo dpkg -i step_X.Y.Z_amd64.deb
 ```
 
 Test:
