expenv.sh - Expand environment variables (shell script)

Expenv.sh evaluates shell expressions, e.g. ${var}, $var, $(cmd), reading from a file or stdin. Supports stdout or inplace replacement.

Download and Installation

Simply download the expenv.sh file or use a one-liner:

# Download
$ curl -o expenv.sh -- https://raw.githubusercontent.com/blang/expenv.sh/master/expenv.sh && chmod +x ./expenv.sh
# Download and install
$ curl -o expenv.sh -- https://raw.githubusercontent.com/blang/expenv.sh/master/expenv.sh && chmod +x ./expenv.sh && mv ./expenv.sh /usr/bin/

Usage

$ cat inputfile | expenv.sh > outputfile
$ expenv.sh -f inputfile > outputfile
$ expenv.sh < inputfile > outputfile
$ expenv.sh -i -f inputfile // Replace inplace

Example input:

My PWD is $PWD
Whoami: ${USER}
I'm using $TERM
Supporting $(echo commands) now!

Motivation

I need to make config files more dynamic using environment variables. In a docker environment this is a big issue for me. I wrote a small golang project (expenv) to solve this, until Reddit-User vanwho pointed out a shell one-liner which i adopted in this script.

Contribution

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

License

See LICENSE file.