expenv - Expand environment variables

Expenv replaces ${var} or $var in the input to the values of the current environment variables. Supports stdin/stdout and files.

Installation

You could use one of the snippets below or go to the releases page and select the proper binary file, make sure to add it to your path.

Installer

curl -o- -L https://raw.githubusercontent.com/TheWolfNL/expenv/master/installer.sh | bash

Examples

$ expenv -f inputfile > outputfile
$ expenv < inputfile > outputfile
$ expenv -i -f inputfile // Replace inplace

Example input:

My PWD is $PWD
Whoami: ${USER}
I'm using $TERM
Expand $empty but don't expand $$empty
Don't expand $(echo empty)

As mentioned in the above example, two special cases exist:

• $$ is converted to $, allowing you to pass in literal-dollar-signs
• $( is not converted, allowing your input to contain subshell like behaviour

Motivation

I need to make config files more dynamic using environment variables. In a docker environment this is a big issue for me.

Contribution

Feel free to make a pull request. For bigger changes create a issue first to discuss about it.

License

See LICENSE file.