OVERVIEW
========
libgetopt.sh is a bash implementation of getopt function.
SYNOPSIS
========
getopt CALLBACK_FUN_NAME [ARGS]
FEATURES
========
* short options that starts with "-"
* long options that start with "--"
* short options bundling
* short option argument that starts right after option name(like -Hlocalhost)
* long option argument that separated from option name with "="(like --host=localhost)
* support of "--" argument for denoting of options end
DESCRIPTION
===========
getopt parses positional arguments specified after a callback funcion
name and execute a specified callback function for every parsed option.
Generally getopt should be called like this:
getopt process_opts "$@"
Where process_opts is a callback for processing a parsed option.
Callback is called with 2 arguments. The first is an option name.
The second is an expected option argument. What is "expected option
argument"? getopt doesn't known about mandatory arguments for options.
It simply parse what looks like a mandatory option argument and
pass it to callback for processing. E.g. "localhost" will be $2 value
for every of the next args:
-Hlocalhost
-H localhost
--host=localhost
--host localhost
A callback should decide based on the option name(generally) whether
that option comes with an argument or not. If this option must come with
an argument, then callback can use $2 and returns 1 to
indicate that $2 must be removed from the positional arguments list.
Thus, getopt willn't parse it as an option name in the next iteration.
Otherwise, callback must returns 0.
RETURN VALUE
============
getopt returns a number of positional argument with options,
that can be removed from positional arguments list to easily
work with non-option arguments.
Callback function must returns 1 if an option specified in $1 comes with
argument(i.e. we use value in $2 as an option argument). Otherwise,
callback must returns 0.
NOTES
=====
According to bash manual we can specify a number from 0 to 255(including)
to return function. Thus, max number of positional arguments with options
and their arguments can be 255.
EXAMPLES
========
process_opts()
{
echo "opt '$1' with something that can be it's argument '$2'"
return 0
}
source ./libgetopt.sh
getopts process_opt "$@"
shift $?