Python Debugging Snippets

PDB is Python Debugger. It is in the standard library though there are other debuggers and GUI ones.

# Debug a script with Python Debugger (PDB), part of standard library
python -m pdb pyfile.py
# See https://docs.python.org/3/library/pdb.html
# Commands are similar to GDB

# Debug interactively with PDB
import pdb
import buggyscript
buggyscript.crash()
# Post mortem command to PDB at crash
pdb.pm()

# Start debugging in program with console
import pdb
pdb.set_trace()
# run program with PDB console

# Set a breakpoint in a program
breakpoint()

PDB Console

Also accepts valid python

# Help
help

# list, see current code line - same as GDB
l

# next, go through next line of code - same as GDB
n

# continue, until next breakpoint - same as GDB
c

# step into a statement, function - same as GDB
s

# return
r

# print variables - same as GDB
p variable_name

# breakpoint set on line of current file
b 20
break 4

# Breakpoint in temporary place, breakpoint will only occur once - same as GDB
tbreak 6

# unt(il) line number
until 6
# Continue execution until the line with a number greater
# than the current one is reached or until the current frame returns

See Also

• GDB and LLDB Snippets - GDB and LLDB Debugger Snippets for similar commands