diff --git a/ESXi-GetPercDriveTemps.sh b/ESXi-GetPercDriveTemps.sh
index ed23dcc..864fbd4 100755
--- a/ESXi-GetPercDriveTemps.sh
+++ b/ESXi-GetPercDriveTemps.sh
@@ -22,7 +22,7 @@ for c in $(/opt/lsi/perccli64/perccli64 show | grep PERC | cut -d' ' -f 3); do
 				model=$(echo "${info}" | grep "Model Number" | cut -d'=' -f 2)
 				temp=$(echo "${info}" | grep Temperature | cut -d'=' -f 2)
 				tmp="${model} (SN:${sn})"
-				c=0; spc=''; spc1=`expr 44 - ${#tmp}`; until [ ${c} = ${spc1} ]; do spc="${spc} "; ((c++)); done
+				c=0; spc=''; spc1=`expr 44 - ${#tmp}`; until [ ${c} = ${spc1} ]; do spc="${spc} "; c=`expr c + 1`; done
 				echo "    - Slot #${ss} -${tmp}${spc}${temp}"
 			fi
 		done