Break points:
b F Set a break-point at function F.
b *A Set a break-point at absolute address A
b N Set a break-point at line number N.
b N:F Set a break-point at line number N at file F.
info b Lists break-points.
cond B cond Set a condition to a break-point B.
cond B Remove the condition of a break-point B.
delete B Delete a break-point B.
Stepping:
stepi or si Execute one machine instruction (follows a call).
step or s Execute one C-program statement (steps into functions).
stepi N Do N machine instructions.
nexti or ni Same as si but execute calls as one instructions.
next or n Same as ni but execute functions as one statement.
bt Show names of the stack frames.
up Go up one stack frame.
down Go down one stack frame.
Examining:
info reg List contents of registers.
p V Print contents of a variable V.
x /CT A Examining memory where:
C number of units to display.
T x hex integer.
d dec integer.
u unsigned dec integer.
o octal integer.
c character.
s null terminated string.
i as machine instruction.
A an absolute address or
$reg pointed by some register.