Ubuntu add directory to Python path

Create a .bash_profile in your home directory. Then, add the line

PYTHONPATH=$PYTHONPATH:new_dir
EXPORT $PYTHONPATH

Or even better:

if [ -d "new_dir" ] ; then
  PYTHONPATH="$PYTHONPATH:new_dir"
fi
EXPORT $PYTHONPATH

The .bash_profile properties are loaded every time you log in.

The source command is useful if you don't want to log in again.

@fedorqui's answer above was almost good for me, but there is at least one mistake (I am not sure about the export statement in all caps, I am a complete newbie). There should not be a $ sign preceding PYTHONPATH in the export statement. So the options would be:

Create a .bash_profile in your home directory. Then, add the line

PYTHONPATH=$PYTHONPATH:new_dir
export PYTHONPATH

Or even better:

if [ -d "new_dir" ] ; then
  PYTHONPATH="$PYTHONPATH:new_dir"
fi
export PYTHONPATH