# print content of configuration file
cat config.txt
# expected output:
# server: $SERVER_URL
# username: $USER_NAME
# password: $USER_PASSWORD
# load environment variables
source .env
# replace environment variables in file content
envsubst < config.txt
# expected output
# server: https://gitlab.com/skofgar
# username: foo_user
# password: mymonkey
# replace environment variables and write to new file
envsubst < config.txt > confidential_config.txt
# pipe into less
envsubst < config.txt | less
# pipe a deployment "deploy.yml" into kubectl apply
envsubst < deploy.yml | kubectl apply -f -