docs: add missing '-p' flag to mkdir command in the example

When passing a path that has some parent directories to mkdir command
you also need to pass '-p' flag to tell it to make the parent directories
as needed.

Otherwise you will get an error like this:
mkdir: cannot create directory `src/main/java/com/example/cmdline': No
such file or directory

This patch fixes this documentation as it was suggested at
https://groups.google.com/d/msgid/bazel-discuss/e3d20e6e-9b6f-410f-b80c-67afa9ebc9f9%40googlegroups.com?utm_medium=email&utm_source=footer

--
Change-Id: I3075ac66bb7cf42f97139246471e2120838da1e6
Reviewed-on: https://bazel-review.googlesource.com/#/c/3102/
MOS_MIGRATED_REVID=117708676

1 files changed, 1 insertions, 1 deletions

diff --git a/site/docs/getting-started.md b/site/docs/getting-started.md
index 613793c2b5..1d029216d4 100644
--- a/site/docs/getting-started.md
+++ b/site/docs/getting-started.md
@@ -152,7 +152,7 @@ can refer to targets defined in other BUILD files using the syntax
 file:
 
 {% highlight bash %}
-$ mkdir src/main/java/com/example/cmdline
+$ mkdir -p src/main/java/com/example/cmdline
 $ cat > src/main/java/com/example/cmdline/Runner.java <<EOF
 package com.example.cmdline;