# Miller environment variables

The following environment variables affect how Miller works:

* `MLRRC`: see [Customization](customization.md).
* `MLR_NO_COLOR`, `NO_COLOR`, `MLR_ALWAYS_COLOR`, `MLR_KEY_COLOR`, `MLR_VALUE_COLOR`, `MLR_PASS_COLOR`, `MLR_FAIL_COLOR`, `MLR_REPL_PS1_COLOR`, `MLR_REPL_PS2_COLOR`, `MLR_HELP_COLOR`: see [Output Colorization](output-colorization.md).
* `MLR_REPL_PS1`, `MLR_REPL_PS2`: see [REPL](repl.md).

