Fix another typo in the prereq check.
diff --git a/content/installation/step-by-step.md b/content/installation/step-by-step.md
index d80a31a..1b6e011 100644
--- a/content/installation/step-by-step.md
+++ b/content/installation/step-by-step.md
@@ -127,7 +127,7 @@
 jiri profile os-packages v23:base
 
 # Run the package installation command as root.
-if [ -z "$(jiri profile os-packages v23:base)" ]; then
+if [ -n "$(jiri profile os-packages v23:base)" ]; then
   sudo $(jiri profile os-packages v23:base)
 fi
 ```