diff --git a/bin/output.sh b/bin/output.sh
index a225de4164c..e550105f6a5 100644
--- a/bin/output.sh
+++ b/bin/output.sh
@@ -1,6 +1,11 @@
 #!/bin/sh
 
-# Output colorized strings
+# Output colorized strings.
+#
+# Usage:
+#
+# . $(dirname "$0")/output.sh
+# output <color> "Foobar"
 #
 # Color codes:
 # 0 - black
diff --git a/bin/package-update.sh b/bin/package-update.sh
index 616d16ea330..00cd1dc635d 100755
--- a/bin/package-update.sh
+++ b/bin/package-update.sh
@@ -1,5 +1,6 @@
 #!/bin/sh
 
+# See output.sh for an explanation of the available color codes.
 . $(dirname "$0")/output.sh
 
 if [ ! -d "packages/" ]; then
diff --git a/bin/prefix-vendor-namespaces.sh b/bin/prefix-vendor-namespaces.sh
index 0360e08bd04..ef47652c4b3 100755
--- a/bin/prefix-vendor-namespaces.sh
+++ b/bin/prefix-vendor-namespaces.sh
@@ -1,5 +1,6 @@
 #!/bin/sh
 
+# See output.sh for an explanation of available the color codes.
 . $(dirname "$0")/output.sh
 
 output 6 "Prefixing the appropriate vendor namespaces with Automattic\WooCommerce\Vendor"
@@ -7,9 +8,10 @@ output 6 "Prefixing the appropriate vendor namespaces with Automattic\WooCommerc
 # Replace "League\Container" in "use" and "namespace" with "Automattic\WooCommerce\Vendor\League\Container".
 REGEX='s/^[[:space:]]*(use|namespace)[[:space:]]*(League\\Container)/\1 Automattic\\WooCommerce\\Vendor\\\2/g'
 
-# macOS and Linux have a slightly different syntax for 'sed -i' so we need two versions.
-if [[ "$OSTYPE" == "darwin"* ]]; then
-  find ./vendor/league/container -type f -name '*.php' -print0 | xargs -0 sed -i '' -E -e "$REGEX"
-else
-  find ./vendor/league/container -type f -name '*.php' -print0 | xargs -0 sed -i -E -e "$REGEX"
-fi
+find ./vendor/league/container -iname '*.php' -exec sed -i '.bak' -E -e "$REGEX" {} \;
+find ./vendor/league/container -name "*.php.bak" -type f -delete
+
+# Replace too in the composer.json file for the package.
+sed -i '.bak' -E -e "s/\"(League\\\\\\\Container)/\"Automattic\\\\\\\WooCommerce\\\\\\\Vendor\\\\\\\\\1/g" vendor/league/container/composer.json
+rm -f vendor/league/container/composer.json.bak
+