/usr/bin/attr: invalid option -- '-'
Unrecognized option: ?
Usage: attr [-LRSq] -s attrname [-V attrvalue] pathname  # set value
       attr [-LRSq] -g attrname pathname                 # get value
       attr [-LRSq] -r attrname pathname                 # remove attr
       attr [-LRq]  -l pathname                          # list attrs
      -s reads a value from stdin and -g writes a value to stdout