getopts(1) -- Parse CLI options

SYNOPSIS

getopts [options ...]
getopts [options ...] | while read -l key value; ...; end

DESCRIPTION

getopts is a tool to help parsing command-line arguments. It is designed to process command line arguments that follow the POSIX Utility Syntax Guidelines. If no arguments are given it returns 1.

USAGE

In the following example:

getopts -ab1 --foo=bar baz

And its output:

a
b    1
foo  bar
_    baz

The items on the left represent the option flags or keys associated with the CLI. The items on the right are the option values. The underscore _ character is the default key for arguments without a key.

Use read(1) to process the generated stream and switch(1) to match patterns:

getopts -ab1 --foo=bar baz | while read -l key option
    switch $key
        case _
        case a
        case b
        case foo
    end
end

OPTIONS

None.

EXAMPLES

The following is a mock of fish(1) CLI missing the implementation:

function fish
    set -l mode
    set -l flags
    set -l commands
    set -l debug_level

    getopts $argv | while read -l key value
        switch $key
            case c command
                set commands $commands $value

            case d debug-level
                set debug_level $value

            case i interactive
                set mode $value

            case l login
                set mode $value

            case n no-execute
                set mode $value

            case p profile
                set flags $flags $value

            case h help
                printf "usage: $_ [OPTIONS] [-c command] [FILE [ARGUMENTS...]]\n"
                return

            case \*
                printf "$_: '%s' is not a valid option.\n" $key
                return 1
        end
    end

    # Implementation
end

BUGS

getopts does not read the standard input. Use getopts to collect options and the standard input to process a stream of data relevant to your program.
A double dash, --, marks the end of options. Arguments after this sequence are placed in the default underscore key, _.
The getopts described in this document is not equivalent to the getopts builtin found in other shells. This tool is only available for fish(1).

AUTHORS

Jorge Bucaran j@bucaran.me.

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