Set Dokku environment variables in bulk from a .env file. assumed to run from the application directory

dokku-env-file.sh

#!/bin/bash
set -euo pipefail
IFS=$'\n\t'

env_file=${1:-}
if [[ -z "$env_file" ]]; then
    echo -e "usage: $0 env_file"
    exit 1
fi

while read -r env; do
    [[ -n "${env}" ]] || continue # skip blank lines
    [[ "${env}" != \#* ]] || continue # skip commented lines
    dokku config:set --no-restart "${env}" < /dev/null
done < "${env_file}"