Process command-line arguments (or args, if specified) and check for legal options. getopts is used in shell-script loops and is intended to ensure standard syntax for command-line options. Standard syntax dictates that command-line options begin with -. Options can be stacked: i.e., consecutive letters can follow a single -. End processing of options by specifying -- on the command line. string contains the option letters to be recognized by getopts when running the shell script. Valid options are processed in turn and stored in the shell variable name. If an option is followed by a colon, the option must be followed by one or more arguments. (Multiple arguments must be given to the command as one shell word. This is done by quoting the arguments or separating them with commas. The application must be written to expect multiple arguments in this format.) getopts uses the shell variables OPTARG, OPTIND, and OPTERR.