I've been doing some work with Linux lately, a new thing for me, and feel a bit like I've been thrown into the deep end and told to swim. Today I updated Python to version 2.7 on an EC2 instance.

Amazon Linux (Basic 64-bit Amazon Linux AMI 2011.09 AMI Id: ami-1b814f72) currently comes with Python 2.6.7 on it. At first, I thought I'd just be able to update to 2.7 with yum, but as far as I can tell, there isn't a package for that already.

Joshua Holmes wrote about updating Python, which was a great help. My experienced varied a little, so I thought I'd share in case it is useful to someone else. For example, I didn't want sqllite, but I did want ssl support. Also, there were some cases where I needed to use sudo when logged in as ec2-user.

#!bash
sudo yum install make gcc gcc-c++
sudo yum install openssl-devel.x86_64

cd ~
wget http://python.org/ftp/python/2.7/Python-2.7.tgz
tar xfz Python-2.7.tgz
cd Python-2.7
./configure --prefix=/opt/python2.7 --with-threads --with-ssl --enable-shared
make
sudo make install

cd ~ 
echo '''
 alias python='/opt/python2.7/bin/python'
 PATH=$PATH:/opt/python2.7/bin
 ''' >> .bash_profile
source .bash_profile

echo '''
 /opt/python2.7/lib
 ''' >> opt-python2.7.conf
sudo mv opt-python2.7.conf  /etc/ld.so.conf.d/
sudo ldconfig

python -V
Python 2.7

Notes

Line 26 is output from Python -- not something you input (if that wasn't obvious).

The configure script (line 8 ) specifies which optional libraries will be included in Python. I'm not sure what the typical list includes (for example, which are included in the official Python install for Windows?), but when you run make (line 9), it will report all the missing libraries for Python modules ("Python build finished, but the necessary bits to build these modules were not found"). If you use a module with a missing library in a Python program, you'll get a runtime error.

The echo lines (13-16) are editing your user profile file for bash so that when you type 'python' you'll get the 2.7 version instead of the default 2.6.7 version. I had a situation where I needed to run python under sudo, but root doesn't have the alias, so it kept running 2.6.7. After some unfruitful attempts to add the alias to /etc/profile (sudo doesn't execute that), I just added a symlink and invoked 'python2.7' explicitly (thanks to Chris Brinker):

#!bash
sudo ln -s /opt/python2.7/bin/python /usr/bin/python2.7
sudo python2.7 -V
Python 2.7