slight update to fastdu formatting

files/md5sum-update

@@ -6,7 +6,7 @@ Usage: md5sum-update [-r] [list name]
   -r recursive
   list name is md5sums.txt by default
 
-  Check files with "md5sum -m m5sums.txt"
+  Check files with "md5sum -c m5sums.txt"
   '
     exit
 }