diff --git a/macos/runtime_setup_stages/install_gems.sh b/macos/runtime_setup_stages/install_gems.sh
index 501cd16..25f0bab 100755
--- a/macos/runtime_setup_stages/install_gems.sh
+++ b/macos/runtime_setup_stages/install_gems.sh
@@ -4,13 +4,16 @@ ROOTDIR=$(dirname "$0")
 ROOTDIR=$(cd "$ROOTDIR/../.." && pwd)
 source "$ROOTDIR/shared/lib/library.sh"
 
-RUBY_VERSIONS=($(cat "$ROOTDIR/shared/definitions/ruby_versions"))
+read -ra RUBY_VERSIONS < "$ROOTDIR/shared/definitions/ruby_versions"
 LAST_RUBY_VERSION=${RUBY_VERSIONS[${#RUBY_VERSIONS[@]} - 1]}
 
 if [[ -e /usr/local/rvm/bin/rvm-exec ]]; then
 	RVM_EXEC=/usr/local/rvm/bin/rvm-exec
 elif [[ -e $HOME/.rvm/bin/rvm-exec ]]; then
 	RVM_EXEC=$HOME/.rvm/bin/rvm-exec
+elif [ "${GITHUB_ACTIONS:-false}" = 'true' ]; then
+	\curl -sSL https://get.rvm.io | bash
+	RVM_EXEC=$HOME/.rvm/bin/rvm-exec
 else
 	echo "*** ERROR: you must have RVM installed"
 	exit 1
@@ -27,6 +30,8 @@ ALL_RUBIES_OK=true
 for RUBY_VERSION in "${RUBY_VERSIONS[@]}"; do
 	if run_ruby "$RUBY_VERSION" ruby -v &>/dev/null; then
 		echo "Ruby $RUBY_VERSION: ok"
+	elif [ "${GITHUB_ACTIONS:-false}" = 'true' ]; then
+		rvm install "ruby-$RUBY_VERSION"
 	else
 		echo "Ruby $RUBY_VERSION: NOT INSTALLED! Please install it!"
 		ALL_RUBIES_OK=false