getopts | Node.js CLI options parser | Command Line Interface library

You failed to declare either -t or -p as taking an argument, so OPTARG isn't set for either option.

getopts optstring name [args]

getopts is used by shell procedures to parse positional parameters. optstring contains the option characters to be recognized; if a character is followed by a colon, the option is expected to have an argument, which should be separated from it by white space.

A correct call to getopts would be

IT seems that Pushover migrated their API to different IP addresses in order to counteract a DDoS attack on it.

Since our firewall was only configured to allow traffic to the old addresses, our System was unable to send messages to the IP.

Why LWP::Useragent flagged this as "invalid arguments" is currently beyond me, but the problem at hand is currently solved.

How can this be remedied in Bash?

Well, by patching the sources. But I wouldn't like to do it, I believe the current behavior is the right one.

You could add an additional function to getopt.c and expose it via some special variable in variables.c that would allow manipulating getopts internal state.

Or even simpler - I see getopts.def loadable builtin which you could patch to add some additional option to serialize/deserialize getopts state.

And you can also provide your own implementation of getopts as a bash function with your custom semantics and custom state serializer/deserializer.

Can anyone shed any light on

From posix getopts:

If the application sets OPTIND to the value 1, a new set of parameters can be used: either the current positional parameters or new arg values. Any other attempt to invoke getopts multiple times in a single shell execution environment with parameters (positional parameters or arg operands) that are not the same in all invocations, or with an OPTIND value modified to be a value other than 1, produces unspecified results.

From that we know:

• setting OPTIND=1 resets the internal state of getopt ()
• it is not specified what should happen if you modify OPTIND.

The behavior you are seeing is documented - setting OPTIND=1 as $OPTIND is equal to 1 resets getopt(), which results in endless loop, as one would expect. Except for that, bash documentation does not specify what should happen when you modify OPTIND. Do not do it. Your expectation that setting OPTIND to custom value will affect getopts in specific ways is not based on anything. It will not.

resolve this one issue when writing my wrapper to allow for partial argument/nested getopts handling?

If you are writing your own argument parsing module, do not use getopts and do not depend on undefined, unspecified nor implementation defined behavior. I suggest to do it the same way GNU getopt does - produce a shell source-able string in separate sub-process, instead of relying on global variables OPT* and contributing to spaghetti code.

Do not nest getopts, it is not re-entrant and there is no way to affect it's internal state and it uses global variables. getopts sets OPTIND, it is not required to read it, except for the case when OPTIND is reset to 1, in which case getopts is reset. Any other value may just be ignored. Just call one getopts after another.

Got it! After printing the args as @user1934428 suggested, I've figured out that the last argument is available to the script but not to getopts.

I've tried to understand why and it hit me, a colon is missing after the 'o'!

Instead of while getopts 'p:o' OPTION it should be while getopts 'p:o:' OPTION

as noted in getopts man page:

if a letter is followed by a colon, the option is expected to have an argument, or group of arguments, which must be separated from it by white space.

Note: with the information above I fixed the issue and getopts got the last argument, though it parsed it by spaces, even though it was quoted. It because i sent arguments to main function like this main $@ when i shouldv'e quoted it like this main "$@".

Try this: while processing commnand line options, just collect variables. Only do things with those variables after the options are parsed.

I don't think you want the outer loop (while [ -n "$1" ]; do), unless you want to be able to process multiple subcommands in a single run. That is, do you want this:

Is there a way in bash script to have an option to give an argument but it shouldn't a must?

Yes, there is a way.

getopts does not supports optional arguments. So... you can:

• roll your own bash library for parsing arguments or
• use another tool that has support for optional arguments.

A common tool is getopt that should be available on any linux.

Not working solution, it only works in this case, not with 3 sub parameters

Thanks to Philippe for his comment : Let me know if you think it's not ok, or purpose better and a confirm as answer :)

I changed a couple things, because I realized that explaining all little details in comments would be too long.

Here is the code: