Common pdb Commands

Master the most useful pdb commands for effective debugging.

Navigation Commands

Commands for stepping through code.

# Common pdb navigation:
# l - list current code section
# n (next) - execute next line
# s (step) - step into function
# c (continue) - resume execution
# u (up) - go up one frame
# d (down) - go down one frame
# j lineno (jump) - jump to line

def example():
    x = 1  # Breakpoint here, then n to next
    y = 2  # n again
    z = x + y  # s into any function calls
    return z

# In pdb session:
# (Pdb) l
# (Pdb) n
# (Pdb) s
# (Pdb) c

Commands accepted and executed in pdb

Inspection Commands

Commands for examining variables and state.

# Inspection commands in pdb:
# p expression - print value
# pp object - pretty print object
# whatis variable - show type
# h - help
# h command - help on specific command

def inspect_example(data):
    result = sum(data)
    count = len(data)
    # Breakpoint and inspect
    import pdb; pdb.set_trace()

    # In pdb:
    # (Pdb) p result
    # (Pdb) pp data
    # (Pdb) whatis count

    return result

print("Inspection commands available")

Inspection commands available