IRAFV2.15 or above
written by Divakara Mayya (ydm@inaoep.mx)  

For Mac users I recommend the IAC  SIEpedia page 


Login as root [or iraf] (in most systems use the command "su" or "sudo su")

su
ln -s /home/iraf  /iraf

cd /iraf
mkdir iraf
cd /iraf/iraf

tar zxvf ~ydm/Downloads/iraf.lnux.x86.tar.gz
   ..... for Fedora/SuSe/Ubuntu

make sure you are in csh or tcsh (not bash)

source /iraf/iraf/unix/hlib/irafuser.csh
   ..... beforehand check the hardware "uname -m"
         x86_64 ===> 64 bits 
         i686 ===> 32 bits   MACH = linux
       .... change set old_method          = 1   if there is an error
      (edit this file so that it runs without error).

cd /iraf/iraf/unix/hlib
  ./install -n
In your user login, edit .cshrc or .tcshrc to include 
setenv iraf /iraf/iraf/

to install xgterm ....

login in as iraf
cd /iraf/iraf
tar zxvf ~ydm/Downloads/x11iraf-v2.0BETA-bin.linux.tar.gz

for external packages:

cd extern
 ./configure
make stsdas mcsred ctio