Using Packager and Installer for Linux and UNIX › Installer Functions Overview

Installer Functions Overview

The Installer manages software installations on various target computer operating environments. All functions of the Installer are available through the lsm command and its numerous options at the command line.

Following is an overview of relevant Installer functions:

• Installs a PIF, PKG, AIX, HP-SD, OSX, or RPM product, dialog-driven or in unattended (silent) mode. To customize an unattended installation, a response file can be added.
• Updates an installed PIF product on the target computer. In the case of an update installation, the Installer creates a backup of the installed PIF product. During the update installation, the differences between the previously installed product and the new product are evaluated. Files no longer used are automatically removed from the target computer.
• Resolves all dependencies defined in the product and its components, if needed over several layers, and ensures that all dependent products are installed before the product is installed. Removes all dependent products if possible, and over several layers if needed, when a product is being removed (applies only to dependent products delivered and installed with the product).
• Tests new installation dialogs and creates a response file with the values entered in the dialogs.
• Verifies checksums on the target computer. During product creation, the Packager adds checksums to the prototype file. The PIF product file is secured by a CRC checksum (CRC = Cyclic Redundancy Check). On the target computer, the Installer is aware of this CRC checksum, and alerts you if installed files of the PIF product have been changed subsequent. An installation fails if the PIF product file has been changed from outside.
• Manages effectively shared files during the installation of a PIF product. (A shared file is installed and used by more than one product at the same time.) During an update installation of a PIF product that contains a shared file, this file is updated only if the checksums of the existing and the new file differ, and the modification date of the new file is newer than the existing one. Otherwise, the shared file is not changed.

  The installation of a PIF product aborts if one of the following conditions is true:

  • The file types of shared files differ (for example, a standard file is installed, and a directory should be created with the same name)
  • The targets of a shared link differ
• Checks an installed product for consistency. The product files are checked for existence and access rights.
• Restores files after package removal. If a new PIF installation starts, the Installer notes all files that will be overwritten by the product installation. These files are stored in a specific file, .notremove. The .notremove file is created in the Installer's home directory (/opt/CA/SharedComponents/installer) by default. The file is protected by a checksum and no user can modify it. Additionally, it contains all files that have been overwritten by the new installation.

  If the package is removed and no other package references a not removable file, the entry is removed from .notremove. As a result, the file is not removed it remains with its last content on the system.

• Queries an installed product or product file and shows the product properties and dependency hierarchies.
• Lists all installed products or only the shared components. Prints the version of the Installer used.
• Removes an installed product, in unattended mode if desired.
• After the last PIF product has been removed from the target computer, the Installer removes itself from the target computer (cleanup).
• Displays the progress and informative text at the console in the case a large PIF product with a long installation preparation phase is being installed.
• Installs patches.
• Installs packages multiple times.
• Restores files after failed package installations.
• Leaves files that exist before the first package installation.