The PDB is the built-in Python terminal debugger.

The first step is to add a breakpoint in the code:

import pdb; pdb.set_trace()
  • multiple breakpoints can be added

Now, execute the file. The debugger screen should appear in the terminal.

Common commands:

  • l .: list current line and surrounding code. Omit the dot for subsequent calls to increase range.
  • n: run current line and move to the next statement (step over)
  • s: step into the current statement (step into)
  • c: continue to the next breakpoint (or until program finishes execution)
  • r: returns to the parent level.
  • b <path/to/script:line-number> OR <class-name.method-name> OR <function-name>: add a breakpoint. Examples: b test/charts_test:27, b ChartTopFreeTest.test_topfree_is_correct
  • h: help