diff --git a/cp_sh b/cp_sh
index f54cf6b..76226ad 100755
--- a/cp_sh
+++ b/cp_sh
@@ -4,7 +4,7 @@
 # @version 0.2
 
 function free_disk() {
-  df "$1" | grep '/dev/' | sed -r -e "s/[\t\ ]+/ /g" | cut -d ' ' -f 4
+  df "$1" | tail -n1 | sed -r -e "s/[\t\ ]+/ /g" | cut -d ' ' -f 4
 }
 
 md5="2cp"