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I want to take an input, a bash command, and be able to execute that input from my CPP program. This is for school and we are not allowed to use "system" so I do not know any other way to do this. Also, the program can take up to 3 commands via pipe. I've looked up how to do this but it just gets more confusing. If there are any resources or a question similar to this that has been answered please link. Thanks.

user15293292
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    There's a whole family of `exec` functions you can use. – tadman Apr 01 '21 at 21:44
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    [This](https://man7.org/linux/man-pages/man2/execve.2.html) – Zoso Apr 01 '21 at 21:44
  • Won't work for intrinsic bash commands of course, only executables. But you can also run bash directly using `execxy()` and pass commands via a pipe for example. – πάντα ῥεῖ Apr 01 '21 at 21:47
  • Does [this](https://stackoverflow.com/a/4209206/1851678) answer your question? It uses the example of executing `echo` from the program. – Zoso Apr 01 '21 at 21:47
  • I apologize: I marked the wrong question as duplicate. But there are *many* questions on SO that can answer this. eg: https://stackoverflow.com/questions/5094063/fork-pipe-and-exec-process-creation-and-communication – William Pursell Apr 01 '21 at 22:21

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Here is a similar question.

Basically, for the shell part, you are going to use fork and some form of exec (e.g., execve) to get that to execute.

For pipes, you're going to have to use the pipe command in C++, which will allow you to write and read from the pipe from separate children (in your case, up to two pipes, so you can create a 2x2 array of file descriptors, as a normal pipe is just a 2 element array). You should write the output of one program into the correct pipe and read it from the pipe in the next child once the first terminates.

Eric Miller
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