Linux如何在不使用QProcess的情况下执行shell命令? [英] How to execute a shell command under Linux unsing QProcess?

问题描述

我试图从Qt应用程序中读取屏幕分辨率，但不使用GUI模块.

I am trying to read the screen resolution from within a Qt application, but without using the GUI module.

所以我尝试使用:

xrandr |grep \* |awk '{print $1}'

通过 QProcess 的

命令，但它显示警告并且不提供任何输出:

command through QProcess, but it shows a warning and does not give any output:

unknown escape sequence:'\\*'

用\\\*重写它无济于事，因为它导致以下错误:

Rewriting it with \\\* does not help, as it leads to the following error:

/usr/bin/xrandr: unrecognized option '|grep'\nTry '/usr/bin/xrandr --help' for more information.\n

我该如何解决?

推荐答案

您必须使用bash并在引号中传递参数:

You have to use bash and pass the argument in quotes:

#include <QCoreApplication>
#include <QProcess>
#include <QDebug>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    QProcess process;
    QObject::connect(&process, &QProcess::readyReadStandardOutput, [&process](){
       qDebug()<<process.readAllStandardOutput();
    });
    QObject::connect(&process, &QProcess::readyReadStandardError, [&process](){
       qDebug()<<process.readAllStandardError();
    });
    process.start("/bin/bash -c \"xrandr |grep \\* |awk '{print $1}' \"");
    return a.exec();
}

输出:

"1366x768\n"

或者:

QProcess process;
process.start("/bin/bash", {"-c" , "xrandr |grep \\* |awk '{print $1}'"});

或者:

QProcess process;
QString command = R"(xrandr |grep \* |awk '{print $1}')";
process.start("/bin/sh", {"-c" , command});

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