使用 QProcess 管道(或命令链)
我正在使用 Qt 并对其进行 bash，需要执行如下操作:
I'm using Qt and bash over it, need to execute something like:
bash: cat file | grep string
在 Qt 中:
QString cmd = "cat file | grep string";
QProcess *process = new QProcess;
process->start(cmd);
process->waitForBytesWritten();
process->waitForFinished();
qDebug() << process->readAll();
问题出在管道(|")中，进程没有返回任何内容.如果没有(|")，比如
The problem is in pipe ("|"), and process returs nothing. If there is no ("|"), like
"cat file"
一切正常.我试过了.喜欢
everything is ok. I tried smth. like
"cat file \| grep string",
"cat file | grep string"
但结果是一样的.如果我复制命令并在 bash 中运行它，一切正常.
but result is the same. If I copy the command and run it in bash everything is ok.
QString::toAscii().data()
和其他转换也有不好的结果.
and other transforms also have bad result.
推荐答案
问题是您不能使用 QProcess 运行系统命令，而只能运行单个进程.因此，解决方法是将您的命令作为参数传递给 bash:
The problem is you cannot run a system command with QProcess, but only a single process. So the workaround will be to pass your command as an argument to bash:
process.start("bash", QStringList() << "-c" << "cat file | grep string");
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