diff --git a/Facebook/command_line_cheat_sheet.md b/Facebook/command_line_cheat_sheet.md
index ffe6ef9..f3011db 100644
--- a/Facebook/command_line_cheat_sheet.md
+++ b/Facebook/command_line_cheat_sheet.md
@@ -18,8 +18,8 @@ jf land                                     | land the change
 # Buck
 |
 -|-
-buck test @mode/dev-nosan local/path/... | run all tests
-
+buck test @mode/dev-nosan local/path/...    | run all tests
+buck build @mode/opt local/path/...         | build optimized version (by default @mode/dev)
 
 # On deman DB
 |