diff --git a/setup-scripts/serverload.sh b/setup-scripts/serverload.sh
index 6945bcb0..110a5981 100755
--- a/setup-scripts/serverload.sh
+++ b/setup-scripts/serverload.sh
@@ -33,7 +33,7 @@ fi
 # Write the output in an infinite loop.
 while true; do
     # CPU usage
-    cpu=$(echo $[100-$(vmstat 1 2|tail -1|awk '{print $15}')]) 
+    cpu=$((100-$(vmstat 1 2|tail -1|awk '{print $15}')))
     sed -i "1iCPU: ${cpu}" $logfile
 
     # Disk Usage