There are different types of installation script:

• Pre-installation scripts (pkg_preinst): These are called before the package is unpacked
• Post-installation scripts (pkg_postinst): These are called after the package is unpacked, and dependencies will be configured
• Pre-removal scripts (pkg_prerm): These are called with installed or at least partially installed packages
• Post-removal scripts (pkg_postrm): These are called after the package's files have been removed or replaced