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+
+Getgopt
+=======
+
+**Getgopt** is an extremely very simple implementation of POSIX C's ``getopt(3)`` function for
+golang. The entire library consists of 4 exported global variables, 1 exported function, and less
+than 100 lines of code (``sed -e '/^$/d' -e '/^\s*\*/d' -e '/^\s*\/\*/d' getgopt.go | wc -l``). I
+wrote this library because I didn't like how all the other alternatives for normal command line
+parsing were so overly complex. Go is all about keeping things simple, so let's keep flag parsing
+simple.
+
+
+Usage
+=====
+
+There is only 1 function for you to use, and that is `getgopt.Getopt()`. The function works *almost*
+the same way that the POSIX C ``getopt`` function works. Here is an example of it's usage:
+
+.. code-block:: go
+
+        package main
+
+        import (
+                "fmt"
+                "os"
+
+                "github.com/Mango0x45/getgopt"
+        )
+
+        func main() {
+                for opt := byte(0); getgopt.Getopt(len(os.Args), os.Args, ":a:bcd", &opt); {
+                        switch opt {
+                        case 'a':
+                                fmt.Printf("Parsed the -a flag with the argument '%s'\n",
+                                        getgopt.Optarg)
+                        case 'b':
+                                fmt.Println("Parsed the -b flag")
+                        case 'c':
+                                /* ... */
+                        case 'd':
+                                /* ... */
+                        case '?':
+                                fmt.Fprintf(os.Stderr, "Invalid flag '%c', read the manpage\n",
+                                        getgopt.Optopt)
+                                os.Exit(1)
+                        case ':':
+                                fmt.Fprintf(os.Stderr, "The flag '%c' requires an argument\n",
+                                        getgopt.Optopt)
+                                os.Exit(1)
+                        }
+                }
+
+                fmt.Printf("The first non-option argument is '%s'\n", os.Args[getgopt.Optind])
+        }
+
+After parsing a flag the ``Getopt()`` function returns true if there are still more flags to parse,
+or false if there are none more. This means that we can use it in a ``for`` or ``while`` loop to
+iterate over all of our arguments. As its arguments, the ``Getopt()`` function takes (in this
+order), the count of command line arguments, the command line arguments, an *optstring*, and a
+pointer to a byte where the parsed flag will be stored. After parsing a flag, the byte that was
+passed as the last parameter will either have the value of the flag or one of ``':'`` and ``'?'``.
+The value of ``opt`` is set to ``'?'`` if the user attempted to pass a flag that was not specified
+by the given *optstring*. If the user specifies a flag that requires an argument without actually
+passing an argument, then ``opt`` will be set to ``':'`` if the first character in the *optstring*
+is ``':'`` and otherwise it will be ``'?'``.
+
+The *optstring* is a string passed as the 3rd argument to ``Getopt()`` which specified which flags
+you want to be able to handle. Each flag you want to handle is given as a single character in the
+string in any order. For example if you want to support the ``-a``, ``-b``, and ``-x`` flags you can
+do::
+
+        getgopt.Getopt(len(os.Args), os.Args, "abx", &opt)
+        /* or */
+        getgopt.Getopt(len(os.Args), os.Args, "bxa", &opt)
+
+If you want a flag to take an argument, you should suffix the character with a ``':'``. So using the
+above example, if we want the ``-b`` flag to take an argument, we could write::
+
+        getgopt.Getopt(len(os.Args), os.Args, "ab:x", &opt)
+
+Finally, by default the ``Getopt()`` function will print diagnostic error messages to standard
+output when the user fails to provide an argument to a flag that expects one or passes an invalid
+flag. If you would like to not have these diagnostics printed you can either prefix the optstring
+with ``':'`` or you can set the ``Opterr`` global variable to ``false``. Both of the following are
+equivalent::
+
+        getgopt.Getopt(len(os.Args), os.Args, ":ab:x", &opt)
+        /* or */
+        getgopt.Opterr = false
+        getgopt.Getopt(len(os.Args), os.Args, "ab:x", &opt)
+
+There is a *slight* difference in behavior though which was explained above.
+
+Finally, there are 3 other global variables you can access, these are ``Optarg``, ``Optind``, and
+``Optopt``. When you parse a flag which requires an argument, that argument can be found as a string
+in the ``Optarg`` variable. ``Optind`` is a variable which during the parsing of the flags holds the
+index of command line argument being parsed. After the flags are parsed though it holds the index of
+the first non-option argument in the provided argument list. ``Optopt`` functions similarly to the
+byte you pass as the functions final argument, but it holds the flag which caused the last parsing
+error.