Ubuntu 10.10默认Python是2.6
Ubuntu 11.04默认python是2.7
这个问题貌似在debian上也会出现
现象就是升级python2.7 python2.7-minimal时提示
Preconfiguring packages ...
Setting up python2.7-minimal (2.7.1-1ubuntu4) ...
Linking and byte-compiling packages for runtime python2.7...
E: pycompile:240: Requested versions are not installed
dpkg: error processing python2.7-minimal (--configure):
subprocess installed post-installation script returned error exit status 3
Errors were encountered while processing:
python2.7-minimal
问题详述可见 https://bugs.launchpad.net/ubuntu/+source/python2.7/+bug/693001
问题出在python2.7-minimal的postinst脚本会去执行
/usr/share/python/runtime.d/public_modules.rtinstall
脚本，在public_modules.rtinstall中需要执行
pycompile -V 2.7 /usr/lib/python2.7 ，而这时候python2.7根本还没装，就导致循环出错了
相关讨论见 ?bug=600529
解决方法：
在提示出错后，修改 /usr/share/python/runtime.d/public_modules.rtinstall ，注释掉所有的内容，
然后 apt-get -f install
待正常后，再执行一次 pycompile -V 2.7 /usr/lib/python2.7/dist-packages 就行了