Secure backup script from deleting by accident

backup/backup.sh

@@ -16,7 +16,6 @@ if [ -z "$1" ]
     tar -xzf ${DATE}.tar.gz
     rm -rf ../api/resource
     cp -Rv ${DATE}/resource ../api/
-
 fi
 
 for i in "${col[@]}"
@@ -39,5 +38,8 @@ if [ -z "$1" ]
     tar -zcf ${DATE}.tar.gz ${DATE}
 fi
 
+# to avoid file deletion, if date to apply is entered with .tar.gz ending
+if [[ $1 =~ ^[0-9]{4}-(0[1-9]|1[0-2])-(0[1-9]|[1-2][0-9]|3[0-1])$ ]]
+  then
     rm -rf ${DATE}
-
+fi