dotenvsubst is a little command line utility to substitute environment variables
cargo install dotenvsubst. You need to have Cargo installed.
dotenvsubst [ENVFILE]
Standard input is copied to standard output, with reference to environment variables of the form ${VARIABLE} being replaced with corrisponding values read from the specified ENVFILE. If no ENVFILE is specified, the program looks for a .env file in the current directory.
The syntax for the ENVFILE is composed of variables on new lines in the form of NAME=VALUE.
Using a custom .env_custom ENVFILE on bash:
cat file.sh | dotenvsubst .env_custom > file_env_custom.sh
Using default .env file in Powershell:
Get-Content file.sh | dotenvsubst > file_env.sh