Chapter 2, Debugging and Profiling Python Scripts

1. To debug the program, the pdb module is used.

2. a) Before running ipython3, install using sudo apt-get install ipython3.
   b) %lsmagic.
3. A global interpreter lock is a mechanism used in computer language interpreters to synchronize the execution of threads so that only one native thread can execute at a time
4. Following are the answers:

a) PYTHONPATH: It has a role similar to PATH. This variable tells the Python interpreter where to locate the module files imported into a program. It should include the Python source library directory and the directories containing Python source code. PYTHONPATH is sometimes preset by the Python installer.

b) PYTHONSTARTUP: It contains the path of an initialization file containing Python source code. It is executed every time you start the interpreter. It is named as .pythonrc.py in Unix and it contains...