PC-IRAF Installation Guide

2.3. Merge local revisions back into the new system

If this is a new IRAF installation this step can be skipped. Otherwise, once the new system has been restored to disk any local revisions made to the previous IRAF installation should be merged back into the new system. See §2.1.1 for a list of the files most likely to be affected. When propagating revisions made to these files, be sure to not replace the entire file with your saved version, as the version of the file in the new release of IRAF will often contain important additions or changes which must be preserved. It is best to merge your revisions into the version of the file which comes with the new IRAF.^* This task will be easier if the revisions have been localized as far as possible, e.g., keep all termcap additions together at the head of the file, so that they may merely be transferred to the new file with the editor. The task of propagating revisions will also be much easier if detailed notes have been kept of all revisions made since the the last release was installed.

Beginning with IRAF version 2.8, one should no longer install locally added software in the core system LOCAL package. This significantly complicates updates and is no longer necessary as, due to the layered software enhancements introduced in V2.8 IRAF, it is now straightforward for each site to maintain their own custom LOCAL package external to the core IRAF system. The core system LOCAL is now only a template-local to be copied and used as the starting point for a custom LOCAL layered package. The layered software enhancements, and the procedure for building a custom LOCAL, are discussed further in the PC-IRAF Site Manager's Guide.

^*The UNIX utility diff is useful for comparing files to see what has changed.