diff --git a/check_time_machine_currency.sh b/check_time_machine_currency.sh
index 8123de0..39255ec 100755
--- a/check_time_machine_currency.sh
+++ b/check_time_machine_currency.sh
@@ -55,7 +55,12 @@ fi
 
 # Check to see if we're running Mavericks as Time Machine runs a little differently
 osVersion=`sw_vers -productVersion | grep -E -o "[0-9]+\.[0-9]"`
-isMavericks=`echo $osVersion '< 10.9' | bc -l`
+function version { echo "$@" | awk -F. '{ printf("%03d%03d\n", $1,$2); }'; }
+if [ "$(version "$osVersion")" -gt "$(version "$10.9")" ]; then
+    isMavericks=0
+else
+    isMavericks=1
+fi
 
 if [ $isMavericks -eq 0 ]
 then
@@ -105,4 +110,4 @@ then
 else
     printf "CRITICAL - Could not determine the last backup date for this Mac.\n"
     exit 2
-fi
\ No newline at end of file
+fi