Purpose	Example
the program	$ cat inf.c
	#include
	int main() {
	int x;
	x = 1;
	while ( x < 4 ) {
	printf("The value of x = %d\n", x++);
	}
	return 0;
	}
compile with -g	$ cc -g inf.c -o inf
execute with gdb	$ gdb inf
	GNU gdb (GDB) Red Hat Enterprise Linux (7.0.1-32.el5_6.2)
	Copyright (C) 2009 Free Software Foundation, Inc.
	License GPLv3+: GNU GPL version 3 or later
	This is free software: you are free to change and redistribute it.
	There is NO WARRANTY, to the extent permitted by law. Type "show copying"
	and "show warranty" for details.
	This GDB was configured as "x86_64-redhat-linux-gnu".
	For bug reporting instructions, please see:
	...
	Reading symbols from /home/sanjeev/_/inf...done.
list (l)	(gdb) list
	1 #include
	2
	3 int main() {
	4    int x;
	5
	6    x = 1;
	7      while ( x < 4 ) {
	8      printf("The value of x = %d\n", x++);
	9    }
	10
break (b) at line 1	(gdb) break 1
	Breakpoint 1 at 0x4004a0: file inf.c, line 1.
run (r) up to 1	(gdb) run
	Starting program: /home/sanjeev/_/inf
	warning: no loadable sections found in added symbol-file system-supplied DSO at 0x2aaaaaaab000
	Breakpoint 1, main () at inf.c:6
	6 x = 1;
print (p) the value of x	(gdb) print x
	$1 = 0
go to next line	(gdb) next
	7 while ( x < 4 ) {
statement to run	(gdb) p x
value of x	$2 = 1
	(gdb) n
	8 printf("The value of x = %d\n", x++);
	(gdb) p x
	$3 = 1
	(gdb) n
output of the program	The value of x = 1
	7 while ( x < 4 ) {
	(gdb) p x
	$4 = 2
	(gdb) n
	8 printf("The value of x = %d\n", x++);
	(gdb) p x
	$5 = 2
print address of x	(gdb) p &x
	$6 = (int *) 0x7fffffffe6cc
	(gdb) n
output of the program	The value of x = 2
	7 while ( x < 4 ) {
	(gdb) p x
	$7 = 3
	(gdb) n
	8 printf("The value of x = %d\n", x++);
	(gdb) p x
	$8 = 3
	(gdb) n
output of the program	The value of x = 3
	7 while ( x < 4 ) {
	(gdb) p &x
	$9 = (int *) 0x7fffffffe6cc
	(gdb) p x
	$10 = 4
print 4 bytes at &x	(gdb) x/4b &x
	0x7fffffffe6cc: 00000100 00000000 00000000 00000000
print 1 word at &x	(gdb) x/1w &x
	0x7fffffffe6cc: 00000000000000000000000000000100
	(gdb) n
	11 return 0;
	(gdb) n
	12 }
	(gdb) n
	0x0000003590c1d994 in __libc_start_main () from /lib64/libc.so.6
quit gdb	(gdb) quit
	A debugging session is active.
	Inferior 1 [process 21997] will be killed.
confirm exit	Quit anyway? (y or n) y