diff --git a/orbiter/init.lua b/orbiter/init.lua
index 14bfd3c..a81660a 100644
--- a/orbiter/init.lua
+++ b/orbiter/init.lua
@@ -112,7 +112,7 @@ local function uname()
 end
 
 local function which(prog)
-    return shell ('which %s 2> /dev/null' % prog)
+    return shell ('which '..prog..' 2> /dev/null')
 end
 
 function launch_browser (url,browser)
@@ -125,7 +125,7 @@ function launch_browser (url,browser)
     end
     if not browser then
         local os = uname()
-        if line == 'Darwin' then
+        if os == 'Darwin' then
             browser = 'open'
         else
             for _,p in ipairs(browsers) do