How to run GDB

gdb prog core

$ gdb wc GDB is free software and you are welcome to distribute copies of it under certain conditions; type "show copying" to see the conditions. There is absolutely no warranty for GDB; type "show warranty" for details. GDB 4.16 (alpha-dec-osf4.0), Copyright 1996 Free Software Foundation, Inc... (gdb)

The basic commands
definition	command	examples
run program	run args	(gdb) run -l split.c
debug running process	attach pid	(gdb) attach 1219
set breakpoint	break location	(gdb) b wc.c:112 (gdb) b main
view all breakpoints	info breakpoints	(gdb) i b
delete breakpoint	delete breakpoint-num	(gdb) d 1
single step a line of code	step	(gdb) s
single step (skip funcs)	next	(gdb) n
run till a breakpoint is hit	continue	(gdb) c
display variable	print expr	(gdb) p argv[0] (gdb) p &total_lines
display code	list location	(gdb) l main.c:80
show stacktrace	backtrace	(gdb) bt
change variable	set var=value	(gdb) set x=4