This article describes how to build project dependencies with virtualenv. It is appliable to Pinax. Pinax uses virtualenv by default. It lets the developer have a project-specific python directory, including binaries, packages etc … OpenSuse for example supplies very bad Pinax packages which allows the user to mess with his operating system. It is much better to isolate project dependencies from a project to another for more granular control of the maintenance cost; for example if a package upgrade breaks the user project.

What do you think is the problem when vim starts complaining that it can’t write swap files, postgresql starts complaining that there is no disk space left, when df output is:

>>> df 
Filesystem     1K-blocks     Used Available Use% Mounted on
udev               10240        4     10236   1% /dev
run                10240      156     10084   2% /run
/dev/md1        10403064  1298596   8580184  14% /
shm              8188088        0   8188088   0% /dev/shm
tmpfs            8188088      124   8187964   1% /tmp
/dev/md2       105366664 62467912  37588548  63% /home

This post also credits the awesomeness of Open Source and particularly community driven support

It is common for junior developers and system administrators to be blocked because of permissions. This article describes how to identify and fix a permission issue, as this is a FAQ on StackOverflow.

Identifying permission issues

Here a self explaining case, probably the easiest, which happens when trying to access something which is directly blocked by the lack permissions:

>>> mkdir /mnt/foo
mkdir: cannot create directory `/mnt/foo': Permission denied

Now a more obscure cases. In this example, “james” is the owner of the hello file and thus should be able to read and write it: