interpolator

Interpolator

It is a replacement for the popular tool envsubst which allows you to fill in the environment variables in a given template in a bash-like style. This tool however, introduces failover while the variable filling when one is missing. Also it allows users to provide custom syntax for the variable format and defaults to bash-like style.

Installation

go get -u github.com/paroxp/interpolator

Usage

Out of the box, the tool supports the ${ENV_VAR} syntax:

export GREET="World"; echo "Hello \${GREET}" | interpolator -f
# Hello World

You can amend the pattern of the variables, by adding the -m | --pattern flag:

export GREET="World"; echo "Hello ((GREET))" | interpolator -m "\\(\\(([A-Z0-9]+)\\)\\)"
# Hello World

You can also dry run the thing, to establish which variables are used in the template.

export GREET="World"; echo "Hello \${GREET}" | interpolator --dry
# GREET:		'World'

Testing

go test ./...