Bash Opts

Simple Bash options parser, no shit.

Bash Opts expects you to define a list of options, and then call opts_eval with an array of arguments to parse (usually "$@"). It will then match the given arguments against the defined options, and define variables ready for you to be used.

E.g. the following lines will output Bash Opts:

opts --name=
opts_eval "--name='Bash Opts'"
echo $name

Any remaining arguments that do not match your options cannot start with a dash (protecting against typos and wrong option definitions), and will be collected in an array variable args, also for you to be used.

E.g. this will output foo bar:

opts --name=
opts_eval "foo" "bar" "--name='Bash Opts'"
echo ${args[@]}

More detailed usage example (see ./examples/readme.sh):

#!/bin/bash

opts --[d]ebug --[n]ame= --[f]iles[]=
opts_eval "$@"

echo "debug: $debug"
echo "name: $name"
echo "files: ${files[@]}"
echo "args: ${args[@]}"

Call with:

$ bash examples/readme.sh arg-1 arg-2 -d --name="Bash Opts" -f=path/to/foo.sh -f=path/to/bar.sh
# or: bash examples/readme.sh arg-1 -d -n "Bash Opts" -f path/to/foo.sh -f path/to/bar.sh arg-2
# or: bash examples/readme.sh --debug arg-1 --name="Bash Opts" arg-2 --file=path/to/foo.sh --file=path/to/bar.sh
# or: bash examples/readme.sh --debug --name "Bash Opts" arg-1 --file path/to/foo.sh arg-2 --file path/to/bar.sh

debug: true
name: Bash Opts
files: path/to/foo.sh path/to/bar.sh
args: arg-1 arg-2

Options

Options need to be defined as long names, as in --debug.

Short names

Short names can be defined by enclosing contained characters in square brackes, e.g. --[d]ebug. It is not possible to define a short name without also defining a long name, or to define a short name with characters that are not contained in the long name.

There are three types of options:

Flags

Flags, e.g. --debug, do not take a value.

A flag is defined as just --debug. When evaluated it always sets its corresponding variable to either true or false (as strings). I.e. the condition [[ $debug == true ]] will match when --debug was evaluated.

Variables

Plain variables, e.g. --name=, expect a value.

A variable is defined by terminating the name with an equal sign =. Variables match a single passed argument with an equal sign separating name and value (e.g. --name="Bash Options"), or two passed arguments when the name does not end with an equal sign (e.g. --name "Bash Options").

Arrays

Arrays, e.g. --files[]=, expect a value, too, and can be passed several times.

An Array option will result in an array variable with the same plural name. They match one or many arguments with their singular name.

E.g. --file 1.sh --file 2.sh will evalute to an array variable files which contains two strings 1.sh and 2.sh.

Remaining arguments

Arguments that do not match any of the defined options, and that do not begin with a dash -, will end up in an array variable args.

Such arguments can be given at any position between valid options. However, obviously, they must not sit between a variable option and its corresponding value argument when using the syntax without an equal sign (as in --name foo).

Anything separated with -- will end up in the args array as well:

opts_eval "foo" "bar" "--" "baz"
echo "args: ${args[@]}"
=> foo bar baz

Helper functions

opt

The helper function opt echoes a string to pass an option with the same value as defined at this moment. This is handy for passing options through one command or function to another.

opts --debug
opts_eval "--debug"
opt debug
# => --debug

opts --debug
opts_eval ""
opt debug
# =>

opts --name=
opts_eval "--name=foo"
opt name
# => --name="foo"

opts --name=
opts_eval ""
opt name
# => --name=""

opts --paths[]=
opts_eval "--path=./foo --path=./bar"
opt paths
# => --path="./foo" --path="./bar"

opts --paths[]=
opts_eval ""
opt paths
# =>