CommandBox allows you to access Java System Properties from the CLI and environment variables from your operating system via the ${name_here} mechanism. But CommandBox also gives you the ability to create variables of your own directly in the shell. The scope (life) of these environment variables depends on how and where they are declared.
Every shell instance has its own set of environment variables you can set and read. These live for the duration of the shell and have the same lifespan as Java system properties in the CLI. There is an env namespace of commands for dealing with environment variables.
To set a new variable, you can run this:
You can view the contents of that variable from anywhere in the same shell session like so:
Clear out an environment variable like so:
In addition to the global shell environment, each executing command receives its own set of environment variables that go away when the command finishes executing. Unlike Bash, the parent variables are not copied into each command, but a hierarchy is maintained and when a variable is not found, the parent command is checked and so on until the global shell variables. After that, the Java system properties and then OS's actual environment is checked.
Here is a contrived example of an echo command that run a sub command as part of a command expression (backtick expansion). The sub command sets an environment variable and then outputs it.
The first line will output the text "Cheese" but the second line will output the default value of "myDefaul" since the variable only existed in the inner context of the expression and isn't visible to the outer shell.
Recipes behave like a subshell and any variables set in a recipe will live for the duration of that recipe but will be gone once the recipe exits.
To view the environment variable for the current command context, run:
The output is a JSON serialized struct, which makes it suitable for programmatically accessing.
There is a command to help you debug what variables are set in each command context as well as the global shell. Here we pipe some commands into a recipe for execution. The context for the env debug command has no variables, the recipe command has a variable called inRecipe and the global shell as the 2 variables from the example above.