Lệnh hướng dẫn về dòng lệnh trên Linux

Change access permissions, change mode.

Syntax
       chmod [Options]... Mode [,Mode]... file...

       chmod [Options]... Numeric_Mode file...

       chmod [Options]... --reference=RFile file...

Options
  -f, --silent, --quiet   Suppress most error messages.

  -v, --verbose           Output a diagnostic for every file processed.
  -c, --changes           like verbose but report only when a change is made.

      --reference=RFile   use RFile's mode instead of MODE values.

  -R, --recursive         Change files and directories recursively.
                          Take care to not run recursive chmod on the root '/' directory or any other system directory.

      --help              Display help and exit.

      --version           output version information and exit.