Starting GDB:

$ gdb name-of-executable

Commands table

Params	Description
b/break	Add break point
r/run	Runs the program until a breakpoint or error
c	Continues running the program until the next breakpoint or error
*finish	Continue to end of function.
*f	Runs until the current function is finished
s/step	step into next line or into function
n/next/n N	step next line, don't into function
p	Prints the current value of the variable "var"
bt	Prints a stack trace
u	Goes up a level in the stack
d	Goes down a level in the stack
q	Quits gdb
*tui enable	Enable GDB Text User Interface

Refer: http://www.yolinux.com/TUTORIALS/GDB-Commands.html