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C – Read Linux Command Output in a Buffer Code Example

The code for Read Linux Command Output in a Buffer

/* Func : Read_Linux_CmdOutput()
 * Parameter1 : Linux command to be executed
 * Parameter2 : address of the buffer where output is to be stored
 * Desc : Executes the passed command on console 
 and reads the console output to buff
 */
 
void Read_Linux_CmdOutput(char* command, char** buf)
{
    FILE* fp = NULL;
    char* ret = NULL;
    size_t len = 0;
    fp = popen(command, "r");
    if (getline(&ret, &len, fp) < 0) {
        fprintf(stderr, "whole line can not be read\n");
        strcpy(ret, "");
    }
    if (!strcmp(ret, "")) {
        strcpy(*buf, "");
    }
    else {
        size_t len = strlen(ret);
        if (ret[len - 1] == '\n')
            ret[--len] = '\0';
        strcpy(*buf, ret);
    }
    free(ret);
    pclose(fp);
}

#include <cstdio>
#include <iostream>
#include <memory>
#include <stdexcept>
#include <string>
#include <array>

std::string exec(const char* cmd)
{
    std::array<char, 128> buffer;
    std::string result;
    std::unique_ptr<FILE, decltype(&pclose)> pipe(popen(cmd, "r"), pclose);
    if (!pipe) {
        throw std::runtime_error("popen() failed!");
    }
    while (fgets(buffer.data(), buffer.size(), pipe.get()) != nullptr) {
        result += buffer.data();
    }
    return result;
}