如何在bash中使用程序A的输出作为B的输入？

Question

That is, B has a gets that asks for input, A has a puts that outputs something.

Both A and B are C programs.

How can I use the output of program A as input for B in bash?

What I tried is ./A |./B and ./B |./A , but neither works.

UPDATE

How does stuff in stdout of A goes to stdin of B for ./A|./B ?

Answer 1

Here is an example to get you started:

/* a.c */
#include <stdio.h>
int main() {
    puts("This is a string");
    return 0;
}

Compile this as "a.out".

Here is the program that will catch the string from a.out:

/* b.c */
#include <stdio.h>
int main() {
    char line[1024];
    fgets(line,1023,stdin);
    printf("b.c: %s",line);
    return 0;
}

Compile this as "b.out".

Now run them together:

./a.out | ./b.out

The main principle for pipes to work is that you write to stdout and read stdin. Let me know if you need more help.