Usage: chmod [OPTION]... MODE[,MODE]... FILE...
  or: chmod [OPTION]... OCTAL-MODE FILE...
  or: chmod [OPTION]... --reference=RFILE FILE...
Change the mode of each FILE to MODE.

  -c, --changes like verbose but report only when a change is made
      --no-preserve-root do not treat `/' specially (the default)
      --preserve-root fail to operate recursively on `/'
  -f, --silent, --quiet suppress most error messages
  -v, --verbose output a diagnostic for every file processed
      --reference=RFILE use RFILE's mode instead of MODE values
  -R, --recursive change files and directories recursively
      --help display this help and exit
      --version output version information and exit

Each MODE is of the form `[ugoa]*([-+=]([rwxXst]*|[ugo]))+'.