System managers familiar with the installation of typical UNIX programs should beware that IRAF, being a large system in its own right and not a UNIX program, does not always follow to the usual conventions. It is wise to read and adhere to the installation instructions to avoid problems.

# Prepare the root IRAF directory.
if new installation
    create iraf account
else if updating an old installation
    save locally modified files; delete old system

# Install the files.
login as iraf
unpack the core system distribution
configure the BIN directories

# Merge local revisions into new system.
if updating an old installation
    merge locally modified files back into new system

run the iraf install script to complete the installation
checkout the new system