# Custom Commands

![Custom Commands tab in settings](/projtlauncher/img/screenshots/projtlauncher_dark_settings_general.png)

Pre-launch command runs before the instance launches and post-exit command runs after it exits.

Both will be run in the launcher's working folder with extra environment variables:

- $INST_NAME - Name of the instance
- $INST_ID - ID of the instance (its folder name)
- $INST_DIR - absolute path of the instance
- $INST_MC_DIR - absolute path of Minecraft
- $INST_JAVA - Java binary used for launch
- $INST_JAVA_ARGS - command-line parameters used for launch (warning: will not work correctly if arguments contain spaces)

Wrapper command allows launching using an extra wrapper program (like 'optirun' on Linux)