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What happens if the first argument looks like another getopts parameter?
If -R is encountered and the first argument looks like another getopts parameter, level is set to the default value of 1, and then the $OPTIND variable is reduced by one. The next time getopts goes to grab an argument, it will grab the correct argument instead of skipping it.
How can I detect that no options were passed with getopts?
If the user happens to pass no option, the first invocation of getopts exits the while loop. If none of the options take an argument, the value of OPTIND indicates how many options were passed.
Is there an optional argument for getopts in Bash?
Actually getopts does support optional arguments! From the bash man page: If a required argument is not found, and getopts is not silent, a question mark (?) is placed in name, OPTARG is unset, and a diagnostic message is printed. If getopts is silent, then a colon (:) is placed in name and OPTARG is set to the option character found.
What does it mean when getopts is silent in Bash?
If getopts is silent, then a colon (:) is placed in name and OPTARG is set to the option character found. When the man page says “silent” it means silent error reporting. To enable it, the first character of optstring needs to be a colon:
How to use the getopts syntax in Java?
The getopts syntax 1 where optstring is a list of the valid option letters, 2 varname is the variable that receives the options one at a time, 3 and arg is the optional list of parameters to be processed. 4 If arg is not present, getopts processes the command-line arguments.
How does getopts work in a shell script?
The getopts builtin uses the OPTIND (option index) and OPTARG (option argument) variables to track and store option-related values. When a shell script starts, the value of OPTIND is 1. Each time getopts is called and locates an argument, it increments OPTIND to the index of the next option to be processed.