interpolate-env

#!/bin/bash
# usage: interpolate-env
#
# Replaces ${x} in text from stdin with value of environment variable "x" and
# outputs the updated text to stdout.
#
# Modified from the conda-base repo's CI workflow:
# https://github.com/nextstrain/conda-base/blob/a2da0f5ef7e95f9db31678c2df00bd312c7b754a/.github/workflows/ci.yaml#L109-L111
#
set -eou pipefail

exec perl -pe 's/\$\{(.+?)\}/$ENV{$1}/ge'