How to pass a command line argument from a cpp file and use it in a shell script?

Question

So, I have to create a cpp file that uses my script to search for someones name. I'm pretty new to this so I don't know much but this is what I currently have. Also I have to use system(). Here is my code

#include <iostream>
#include <string>
#include <cstdlib>
using namespace std;

int main (int argc, char *argv[]) {
    system("./findName.sh" + argv[1] );
    return 0;
}

You included <string>. Why not create a std::string with the full command you want to pass to std::system? — Brian61354270
– Brian61354270, Commented Apr 23, 2020 at 20:24

Paul92 · Accepted Answer · 2020-04-23 20:28:53Z

1

The problem is that in C++, string literals (such as "./findName.sh") are not std::string, but pointers. For pointers, addition has another meaning than string concatenation.

You can create a std::string and use it to perform the concatenation:

    std::string scriptName = "./findName.sh";
    std::string command = scriptName + " " + argv[1];

    system(command.c_str());

Don't forget to check the size of argc to make sure there is an argument.

answered Apr 23, 2020 at 20:28

Paul92

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4 Comments

Cholo Over a year ago

I tried this but it is telling me that the command line arguments are not equal to 1, (I wrote this in the shell script)

Paul92 Over a year ago

@Cholo This should be your main function.

Cholo Over a year ago

It is in my main function, but it is saying the message, like if it didn't receive my argument

Cholo Over a year ago

also it tells me "./findName.sh: 1: [: 1: unexpected operator"

dasfex · Accepted Answer · 2020-04-23 20:56:00Z

0

You can use std::system or boost::process for this purposes.

answered Apr 23, 2020 at 20:56

dasfex

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