dotenv-override-cli

It's dotenv-cli, but with the override feature.

Installing

NPM

$ npm install -g dotenv-override-cli

Yarn

$ yarn global add dotenv-override-cli

Usage

$ dotenv <command with arguments>

This will load the variables from the .env file in the current working directory and then run the command (using the new set of environment variables).

Custom .env files

Another .env file could be specified using the -e flag:

$ dotenv -e .env2 <command with arguments>

Multiple .env files can be specified, and will be processed in order:

$ dotenv -e .env3 -e .env4 <command with arguments>

Cascading env variables

Some applications load from .env, .env.local, .env.development and .env.development.local (see #37 for more information). dotenv-override-cli supports this using the -c flag for just .env and .env.local and -c development for the ones above.

Overriding env variables

If you want to override system wide environment variables, use the -o or --override flag.

E.g. if your .env file contains MY_ENV=bar, that will override MY_ENV=foo:

$ MY_ENV=foo dotenv -o <command with arguments>

Check env variable

If you want to check the value of an environment variable, use the -p flag

$ dotenv -p NODE_ENV

Flags to the underlying command

If you want to pass flags to the inner command use -- after all the flags to dotenv-override-cli.

E.g. the following command without dotenv-override-cli:

mvn exec:java -Dexec.args="-g -f"

will become the following command with dotenv-override-cli:

$ dotenv -- mvn exec:java -Dexec.args="-g -f"

or in case the env file is at .my-env

$ dotenv -e .my-env -- mvn exec:java -Dexec.args="-g -f"

Variable expansion

We support expanding env variables inside .env files (See dotenv-expand npm package for more information)

For example:

IP=127.0.0.1
PORT=1234
APP_URL=http://${IP}:${PORT}

Using the above example .env file, process.env.APP_URL would be http://127.0.0.1:1234.

Variable expansion in the command

If your .env file looks like:

SAY_HI=hello!

you might expect dotenv echo "$SAY_HI" to display hello!. In fact, this is not what happens: your shell will first interpret your command before passing it to dotenv-override-cli, so if SAY_HI envvar is set to "", the command will be expanded into dotenv echo: that's why dotenv-override-cli cannot make the expansion you expect.

One possible way to get the desired result is:

$ dotenv -- bash -c 'echo "$SAY_HI"'

In bash, everything between ' is not interpreted but passed as is. Since $SAY_HI is inside '' brackets, it's passed as a string literal.

Therefore, dotenv-override-cli will start a child process bash -c 'echo "$SAY_HI"' with the env variable SAY_HI set correctly which means bash will run echo "$SAY_HI" in the right environment which will print correctly hello

Debugging

You can add the --debug flag to output the .env files that would be processed and exit.

License

MIT