graphcap/termcap/tapecap additions together
at the head of
the file, so that they may merely be transferred to the new file with the
editor. This approach preserves local additions or overrides while ensuring
that any changes made to the body of the standard distributed file are kept.
The task of propagating revisions will also be easier if notes have been kept
of all revisions made since the the last release was installed. This should
be done in the iraf account directory, i.e. $iraf/local.
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 UNIX/IRAF Site Manager's Guide.
*The UNIX utility diff is useful for comparing files to see what has changed.