If you find that the command mkiraf fails to create a proper login.cl, please do the following:

edit /scisoft//all/packages/iraf/iraf/unix/hlib/mkiraf.csh

and replace the first two uncommented lines with

set     iraf    = "/scisoft/all/packages/iraf/iraf/"

set     imdir   = "/scisoft//all/packages/iraf/imdirs"