Download Python 2.5.1 from http://www.python.org/ftp/python/2.5.1/Python-2.5.1.tgz and save to /afs/slac/g/glast/ground/GLAST_EXT/tiger-i386-32bit-gcc41/python if it doesn't already exist.
Change directory to /afs/slac/g/glast/ground/GLAST_EXT/redhat5-i686-64bit-gcc41/python
Ungzip and Untar the file Python-2.5.1.tgz
Change directory to Python-2.5.1
Set the environment variable EXTRA_CFLAGS to "-fPIC"
Execute ./configure --prefix /afs/slac/g/glast/ground/GLAST_EXT/redhat5-i686-64bit-gcc41/python/2.5.1-gl4/gcc41
Execute make
Execute make install
Leave and erase the current directory (Python-2.5.1)

2.5.1-gl5

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redhat4-i686-

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These are instructions for building Python 2.5.1 for the various OSes supported.

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Download pyfits-2.1.1.tar.gz from http://www.stsci.edu/resources/software_hardware/pyfits/pyfits-2.1.1.tar.gz and save to /afs/slac.stanford.edu/g/glast/ground/GLAST_EXT/redhat4-i686-32bit-gcc34/python if it doesn't already exist.
Change directory to /afs/slac.stanford.edu/g/glast/ground/GLAST_EXT/redhat4-i686-32bit-gcc34/python
Extract pyfits-2.1.1.tar.gz
Change directory to pyfits-2.1.1
Execute /afs/slac.stanford.edu/g/glast/ground/GLAST_EXT/redhat4-i686-32bit-gcc34/python/2.5.1-gl5/gcc34/bin/python setup.py install
Leave and erase pyfits-2.1.1

Change directory to /afs/slac.stanford.edu/g/glast/ground/GLAST_EXT/redhat4-i686-32bit-gcc34/python
Extract matplotlib-0.99.1.tar.gz
Change directory to matplotlib-0.99.1/
setenv DISPLAY localhost:0.0
xhost +
Change setup.cfg set tkagg = False , wxagg = False, macosx = False
Execute /afs/slac.stanford.edu/g/glast/ground/GLAST_EXT/redhat4-i686-32bit-gcc34/python/2.5.1-gl5/gcc34/bin/python setup.py build
Execute /afs/slac.stanford.edu/g/glast/ground/GLAST_EXT/redhat4-i686-32bit-gcc34/python/2.5.1-gl5/gcc34/bin/python setup.py install
Leave and erase matplotlib-0.99.1/