optional variable expansions

README.md

@@ -4,17 +4,15 @@ Loads environment files before running a command without polluting your environm
 
 ## Source code
 
-You can find the source code here: [git.milar.in](https://git.milar.in/milarin/loadenv)
+You can find the source code here: [git.milar.in](https://git.tordarus.net/tordarus/loadenv)
 
 ## Installation
 
-If you have Go installed, you can simply go install the program: `go install git.milar.in/milarin/loadenv@latest`
-
-There are pre-compiled executables for various platforms on the [repository](https://git.milar.in/milarin/loadenv/releases).
+If you have Go installed, you can simply go install the program: `go install git.tordarus.net/tordarus/loadenv@latest`
 
 ## License
 
-Distributed under the MIT License. See [LICENSE.md](https://git.milar.in/milarin/loadenv/src/branch/main/LICENSE.md)
+Distributed under the MIT License. See [LICENSE.md](https://git.tordarus.net/tordarus/loadenv/src/branch/main/LICENSE.md)
 
 ## Usage
 
@@ -31,39 +29,53 @@ The variables will only be available to the given command. They will be deleted
 $ cat .env
 # production server configuration
 DATABASE_HOST=prod-server.com
-DATABASE_USER=milarin
+DATABASE_USER=my-username
 DATABASE_PASS=my-super-secure-password
 
 $ # show the 3 last added env variables
 $ loadenv | tail -n 3
 DATABASE_HOST=prod-server.com
-DATABASE_USER=milarin
+DATABASE_USER=my-username
 DATABASE_PASS=my-super-secure-password
 
 $ cat dev.env
 # development server configuration
 DATABASE_HOST=dev-server.com
-DATABASE_USER=milarin
+DATABASE_USER=my-username
 DATABASE_PASS=my-super-secure-password
 
 $ # load dev.env into environment and run the command env. show last 3 lines
 $ loadenv -f dev.env env | tail -n 3
-DATABASE_HOST=dev-server.com
-DATABASE_USER=milarin
+DATABASE_HOST=dev-my-username
 DATABASE_PASS=my-super-secure-password
 ```
 
-environment variables in that file will be expanded:
+### Variable expansions
+
+By default, environment variables in the env file will NOT be expanded:
 
 ```sh
 $ env | grep USER # current value of $USER
-USER=milarin
+USER=my-username
 
 $ cat .env
-# expand $USER reference
+# expand $USER variable
 USERNAME=$USER
 
 $ loadenv | tail -n 1
-USERNAME=milarin
+USERNAME=$USER # contains literal "$USER" instead of "my-username"
 ```
 
+Use `-e` to expand variables in such cases:
+
+```sh
+$ env | grep USER # current value of $USER
+USER=my-username
+
+$ cat .env
+# expand $USER variable
+USERNAME=$USER
+
+$ loadenv | tail -n 1
+USERNAME=my-username # contains original value of $USER variable
+```

main.go

@@ -20,6 +20,7 @@ var (
 
 var ( // flags
 	FlagEnvFilePath       = flag.String("f", ".env", "environment file")
+	FlagExpandRecursively = flag.Bool("e", false, "expand references in reference definitions")
 
 	FlagExpandEnvFiles = SliceFlag{}
 )
@@ -81,7 +82,13 @@ func parseEnvFile(r io.Reader) {
 
 		matches := EnvVarRegex.FindStringSubmatch(s.Text())
 		if len(matches) != 0 {
-			os.Setenv(matches[1], matches[2])
+			key, value := matches[1], matches[2]
+
+			if *FlagExpandRecursively {
+				value = os.ExpandEnv(value)
+			}
+
+			os.Setenv(key, value)
 		} else if s.Text() != "" && !EnvCommentRegex.MatchString(s.Text()) {
 			panic(fmt.Sprintf("invalid env syntax on line %d", l))
 		}