opt2env

opt2env -- parse command line options and set environment variables based on this options
You don't need to parse your options manually -- just write optstring and call opt2env function

Usage

Paste code from opt2env.sh at the beginning of your bash script and call opt2env function with the following options:
opt2env "$USAGE" "$OPTSTRING" "$@"
where OPTSTRING is the string with description of options:
"[-f|--foo|...|{FOO} <argument> example of option][-b|--bar|...|{BAR} another one]..."
Here -f, -foo is example of an option that requires argument. After call of opt2env environment variable FOO will be set to user's value. -b, --bar is example of an option that doesn't require argument. If it's encountered among command line an options, environment varialbe BAR will be set to 1.
USAGE is the brief description of what your script do; can be empty string.
Free arguments are stored in the FREE_ARGUMENTS array.

If invalid command line options are passed, opt2env will notify user and terminate execution.

Note that opt2arg doesn't support options style when argument is passed without space, e.g. -n100 instead of -n 100.

You can echo help based on your OPTSTRING and USAGE. To do this call
echo_help "$USAGE" "$OPTSTRING"

To reduce space taken by opt2env in your code you can use minified version

Examples

usage="demo script"
docstring="[-b|{BAR} its a bar!][-f|--foo|{FOO} <filename> description of this option]"
echo_help "$usage" "$docstring"

will result in

demo script 

    -b its a bar!
    -f|--foo <filename> description of this option
    -h|--help print help

usage="demo script"
docstring="[-b|{BAR} its a bar!][-f|--foo|{FOO} <filename> description of this option]"
opt2env "$usage" "$docstring" "$@"
echo $FOO
echo $BAR
set -- "${FREE_ARGUMENTS[@]}" # set free arguments to positional parameters
echo $1
echo $2

will result in

./demo.sh "one cow" -f Fee -b two
Fee
1
one cow
two

Note, that in example above -f <filename> or --foo <filename> is parametrised argument, so env. variable FOO is set to "Fee". And -b or --bar is switch, so env. varialbe BAR is set to 1, when "two" and "one cow" are free arguments and can be accessed through FREE_ARGUMENTS array. Using set command we've set this free arguments to positional parameters, so they can be accessed though variables $1 and $2.