Command iraf is available as well as the 'normal' method of calling cl directly. Another startup script is xiraf which starts up IRAF in a xgterm. Command shells ecl, ncl and vocl are directly callable as well. Apart from starting IRAF, these scripts also check for the existence of a login.cl in the current directory, and they offer to run mkiraf to create one, if necessary.
Another local addition is the possibility to select the version to run, by checking the version number in login.cl. So, as long as we support an ol;der version, you will get that version in directories that have a login.cl setup for that version. To get the latest version, edit the file or rerun mkiraf in that directory.

A new version of IRAF (2.16) has been installed, along with updates of various utilities The older version of IRAF (2.14.1) will still be available, and if your login.cl file lists the old version, it will use the old version automatically. So to use the new version, rerun mkiraf or edit login.cl to list the version as 2.16 We have implemented a local tweak in the startup scripts: if you set logver'' in your login.cl to “IRAF V2.16-32bit March 2012” you will start the 32-bit version of IRAF in stead of the 64-bit version. This may be needed, since most of STSDAS is not ported to 64-bit architectures (and maybe other tasks and packages as well).
Note that this needs an exact match (eg, don't make it 2.16.0-32bit or whatever) and it only works, if you start iraf through our startup scripts, not when you set IRAFARCH manually and souce the irafuser.csh script from your login environment (if you set it up like that, you are probably an advanced user and you could figure out yourself how to get the right architecture).
Note also, that running the 32-bit version is only useful for those unported tasks. Some newer packages are only available on 64-bit, and you also need 64-bit support for accessing huge data files, and for more efficient use of the CPU. So select 32bit architecture only if you need it!

Our introduction course has a chapter on IRAF.

See also http://iraf.noao.edu/