Extracting tar files to a specific folder(path).....

tar -xvzf <tar filename> -C <path to where we need to extract>

remove non-empty directories

rm -rf <dir name>

Installing IRAF in Fedora 18...

Installing IRAF 2.16 (working absolutely fine)

The newest version of IRAF is much easier to install than older versions. The following steps have been tested on Fedora 18 64-bit, but should work for older Fedora/RHEL (+ clones) installations.
First, we need to install some required packages. Switch to the root user for all steps below. As root:

yum install tcsh ncurses ds9 xpa

We'll be using IRAF with xgterm, so we need to install a required library: libXmu.so.6. For Fedora 18, this is provided in the libXmu-1.1.1-2.fc18.i686 package. Use yum whatprovides libXmu.so.6 to get the correct package for your system. Go ahead and install that with yum:

yum install libXmu-1.1.1-2.fc18.i686

Now, we can go ahead and install IRAF. Then, make the required directories for IRAF:

mkdir -p /home/iraf/iraf/local

Link the directories to the /iraf directory.

ln -s /home/iraf /iraf

Add the IRAF user (not sure if this step is even required any more, but just in case):

useradd -c "IRAF login" -d /iraf/iraf/local -m -s /bin/csh -u 1001 iraf

Change the ownership on the /iraf directory so IRAF can use it:

chown -R iraf:iraf /iraf

Download the IRAF 2.16 tarball and extract it in the /iraf/iraf directory:

wget ftp://iraf.noao.edu/iraf/v216/PCIX/iraf.lnux.x86_64.tar.gz
tar xvfz iraf.lnux.x86_64.tar.gz -C /iraf/iraf

Set the required environmental variable, and run the IRAF install script (most of the questions should be straightforward; say no to IRAF networking and tape driver, since no one uses that stuff any more):

export iraf='/iraf/iraf/'
iraf/unix/hlib/install

In the /iraf/iraf/ directory, make a directory for x11iraf, then download the x11iraf tarball there:

mkdir /iraf/iraf/x11iraf
cd /iraf/iraf/x11iraf
wget http://iraf.noao.edu/x11iraf/x11iraf-v2.0BETA-bin.redhat.tar.gz
tar xvfz x11iraf-v2.0BETA-bin.redhat.tar.gz

Make the required app-defaults directory for x11iraf:

mkdir /usr/lib64/X11/app-defaults

Now run the x11iraf installation script:

./install

Finally, we're going to use the new package repositories feature of IRAF 2.16 to install some useful external IRAF packages, such as rvsao, guiapps, and stsdas. To do this:

cd /iraf/iraf/extern 

./config (and then wait a bit while it gets the repo info)

ls (to list available packages when the config script is done)

make rvsao stsdas guiapps

And now, we can test out our new IRAF installation. Switch back to a normal user and then:

mkiraf (in your home directory -> creates a login.cl file) 

--> choose xgterm as the terminal type
 

ds9 &  --> starts DS9 and sets up the XPA connection that IRAF will use
 

xgterm & --> starts up xgterm which enables IRAF to show its graphics output

in xgterm: cl --> starts up IRAF

NOTE:

If you find any error while executing the command xgterm &

try dis....

yum install ncurses-libs.i686 libstdc++.i686 libgcc.i686

Your problem will be solved :)