Python pdb and Breakpoint Cheat Sheet

python -m pdb script.py

# Debug a script from the command line.

import pdb
import traceback

try:
    main()
except Exception:
    traceback.print_exc()
    pdb.post_mortem()

# Inspect the traceback after an exception.

PYTHONBREAKPOINT=0 python app.py

# Make breakpoint() a no-op during a run.

PYTHONBREAKPOINT=pdb.set_trace python app.py

# Set an explicit hook from the environment.

b 42

# Set a line breakpoint in the current file.

b module.function_name

# Stop when a function is entered.

b 42, user_id == 123

# Pause only when a condition is true.

disable 1
enable 1

# Toggle an existing breakpoint by number.

clear 1

# Remove one breakpoint or all breakpoints.

j 75

# Change the next line to be executed in the current frame.

a

# Display current frame arguments.

p locals()

# Print local variables dictionary.

p globals()

# Print global variables dictionary.

ll

# Show the entire current function body.

display user.balance

# Re-evaluate an expression each time execution stops.

undisplay 1

# Remove one display entry.

import pdb
pdb.run("main()")

# Debug an arbitrary statement string.

import pdb
pdb.runcall(func, arg1, arg2)

# Run a callable under debugger control.

import pdb
pdb.runctx("result = fn(x)", globals(), locals())

# Control execution namespaces when debugging code strings.

alias pl p locals()

# Define a custom shortcut command.