[yqtao@localhost linux]$ cat buging.c 
#include <stdio.h>
int getSum(int n) {
    int sum=0,i;
    for (i=1;i<=n;i++)
        sum+=i;
    return sum;
}
int main(){
    int res=getSum(100);
    printf("1+2+...+100=%d\n",res);
}

// 查看源码
// 查看第几行附近
// 可简写成l 2
(gdb) list 2   
1    #include <stdio.h>
2    int getSum(int n) {
3        int sum=0,i;
4        for (i=1;i<=n;i++)
5            sum+=i;
6        return sum;
7    }

// 查看main函数附近的源码
(gdb) list main
3        int sum=0,i;
4        for (i=1;i<=n;i++)
5            sum+=i;
6        return sum;
7    }
8    int main(){
9        int res=getSum(100);
10       printf("1+2+...+100=%d\n",res);
11   }


// 设置断点
// break +n在第几行设断点
(gdb) break 8
Breakpoint 1 at 0x4004fa: file buging.c, line 8.
// break +函数名 ，在函数名处设断点
(gdb) break getSum
Breakpoint 2 at 0x4004cb: file buging.c, line 3.

//查看断点信息
(gdb) info breakpoints 
Num   Type      Disp Enb Address      What
1    breakpoint   keep y  0x00000000004004fa in main at buging.c:8
2    breakpoint   keep y  0x00000000004004cb in getSum at buging.c:3

// 删除断点
// delete +n 或 d +n
// 如果不加数字则删除全部的断点
(gdb) d 2
(gdb) info breakpoints 
Num   Type      Disp Enb Address      What
1    breakpoint   keep y  0x00000000004004fa in main at buging.c:8

disable +n //关闭断点
enable +n  //启动断点

// 进入gdb
[yqtao@localhost linux]$ gdb buging
// 在main()函数处设断点
(gdb) info breakpoints 
// 运行程序
(gdb) run
Breakpoint 1, main () at buging.c:9
9        int res=getSum(100);

(gdb) step
getSum (n=100) at buging.c:4
4        for (i=1;i<=n;i++)
// 查看代码
(gdb) l
1    #include <stdio.h>
2    int getSum(int n) {
3        int sum=0,i;
4        for (i=1;i<=n;i++)
5            sum+=i;
6        return sum;
7    }
8    int main(){
9        int res=getSum(100);
10       printf("1+2+...+100=%d\n",res);
// 下一步
(gdb) s
5            sum+=i;
// 打印sum的值
// 看到sum是为赋初值的
(gdb) p sum
$1 = 4195633
// info locals
//打印当前断点处所在函数的所有局部变量的值，不包括函数参数。
(gdb) info locals
sum = 4195635
i = 3