The sed class script

The sed installation class provides a method of installing and removing objects that require modification to an existing object on the target machine. (The file must have already been installed by another package.) A sed class action script delivers sed instructions in the format shown in the next example. You can give instructions that will be executed during either installation or removal. Two commands indicate when instructions should be executed. sed instructions that follow the !install command are executed during package installation and those that follow the !remove command are executed during package removal. It does not matter in which order the commands are used in the file.

The sed class action script executes automatically at installation time if a file belonging to class sed exists. The name of the sed class file should be the same as the name of the file upon which the instructions will be executed.

   # comment, which may appear on any line in the file
   !install
   # sed(C) instructions which are to be invoked during
   # installation of the object
   [address [,address]] function [arguments]
      . . .
   

   !remove
   # sed(C) instructions to be invoked during the removal process
   [address [,address]] function [arguments]
      . . .

address, function, and arguments are as defined in the sed(C) manual page. See case studies 5a and 5b for examples of sed class action scripts.