ulimit -c
gdb XXXX core

bt
f [frame #]

save breakpoints [filename]
source [filename]

1. -g

2. file

3. TAP key

4. help

5. run

6. break [filename]:[line#] [if condition]
   break [function name]    [if condition]

7. next
   step
   continue
   finish        (until the end of current function)

8. print   [variable name]
   print   [pointer name ]
   print   *[pointer name ]
   print/x [variable name]

9. watch   [variable name]

10.break

11.finish

12.list

13.set (set var=1)

14.disassemble

15.mem