diff --git a/ssm b/ssm
index 6800e5c..e537d02 100755
--- a/ssm
+++ b/ssm
@@ -151,9 +151,7 @@ spawn() {
 
 cgroup_get_procs() {
 	if service_cgroup_path is dir; then
-		while read -r line; do
-			service_cgroup_procs += "$line"
-		done < "$cgroup_home/$service_cgroup_name/cgroup.procs"
+		mapfile -t service_cgroup_procs < "$cgroup_home/$service_cgroup_name/cgroup.procs"
 	fi
 }; readonly -f cgroup_get_procs