optparse - A BASH wrapper for getopts, for simple command line arguments.


A BASH wrapper for getopts, for simple command-line argument parsing


Optparse requires gnu-sed instead of the default Mac version of sed, which you can do with the following:

brew install gnu-sed --with-default-names

What is this?

A wrapper that provides a clean and easy way to parse arguments to your BASH scripts. It lets you define short and long option names, handle flag variables, and set default values for optional arguments, all while aiming to be as minimal as possible: One line per argument definition.


See sample_head.sh for a demonstration of optparse

1. Define your arguments

Each argument to the script is defined with optparse.define, which specifies the option names, a short description, the variable it sets and the default value (if any).

optparse.define short=f long=file desc="The input file" variable=filename

Flags are defined in exactly the same way, but with an extra parameter value that is assigned to the variable.

optparse.define short=v long=verbose desc="Set flag for verbose mode" variable=verbose_mode value=true default=false

2. Evaluate your arguments

The optparse.build function creates a temporary header script based on the provided argument definitions. Simply source the file the function returns, to parse the arguments.

source $( optparse.build )

That's it!

The script can now make use of the variables. Running the script (without any arguments) should give you a neat usage description.

usage: ./script.sh [OPTIONS]


    -f --file  :  The input file
	-v --verbose  :  Set flag for verbose mode

	-? --help  :  usage

Supported definition parameters

All definition parameters for optparse.define are provided as key=value pairs, seperated by an = sign.


a short, single-letter name for the option


a longer expanded option name


the target variable that the argument represents


the value to set the variable to. If unspecified, user is expected to provide a value.


a short description of the argument (to build the usage description)


the default value to set the variable to if argument not specified


  1. Download/clone optparse.bash
  2. Add
`source /path/to/optparse.bash` 

to ~/.bashrc

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Mar 9, 2022