how to get output system() command in Qt?

Question

I use system() command in Qt. and I want to get output and show it to users. my command is:

system("echo '" + rootPass.toAscii() + "' | su - root -c 'yum -y install " + packageName.toAscii() + "'");

this command can't run when I use it in QProcess (start or execute function) but if i can run this command in QProcess i can get output with QProcess::readAllStandardOutput() function.

also when i used ">" in system command to save output in a file, I receive output when the package completely installed. like bellow:

system("echo '" + rootPass.toAscii() + "' | su - root -c 'yum -y install " + packageName.toAscii() + "' > result.out");

is there any idea about running this command with QProcess, or get output from system() command as soon as write each line.

Answer 1

You can also obtain the output directly from QProcess

QProcess process;
process.start(/* command line stuff */);
process.waitForFinished(-1); // will wait forever until finished

QString stdout = process.readAllStandardOutput();
QString stderr = process.readAllStandardError();

If you don't want to block your event loop, you can always use the signals:

readyReadStandardOutput();
readyReadStandardError();

And then call a function to readAllStandard[Output/Error]

Answer 2

What you want to execute is a shell command. You need to pass it to a shell. Run the following command using QProcess:

/bin/bash -c "your_command | with_pipes > and_redirects"