QProcess: git ls-files | zip

[sonichy]

I want to pack git files on Linux, and terminal work fine.

git ls-files | xargs tar -czvf file.tar.gz

But QProcess has no response no output no error.

{
    ...
    QString cmd = "git ls-files | xargs tar -czvf " + QFileInfo(path).fileName() + ".tar.gz";
    qDebug() << cmd;
    QProcess *process = new QProcess;
    process->setWorkingDirectory(path);
    connect(process, SIGNAL(readyReadStandardOutput()), this, SLOT(processOutput()));
    connect(process, SIGNAL(readyReadStandardError()), this, SLOT(processError()));
    process->start(cmd);
    ...
}

void MainWindow::processOutput()
{
    QProcess *process = qobject_cast<QProcess*>(sender());
    QString s = QString(process->readAllStandardOutput());
    qDebug() << s;
}

void MainWindow::processError()
{
    QProcess *process = qobject_cast<QProcess*>(sender());
    QString s = QString(process->readAllStandardError());
    qDebug() << s;
}

And how to use zip command instead?
(...) run first

zip file.zip -xi (git ls-files | tr "\n" " ")

[jsulm]

@sonichy Please read documentation and use QProcess in a proper way: https://doc.qt.io/qt-5/qprocess.html
Also, if it does not work then at least connect a slot to https://doc.qt.io/qt-5/qprocess.html#errorOccurred and check whether it is called and what the error is. Also https://doc.qt.io/qt-5/qprocess.html#stateChanged can help.
Do not mix command and its parameters in one string when calling start. The documentation shows how to do it properly:

QString program = "./path/to/Qt/examples/widgets/analogclock";
QStringList arguments;
arguments << "-style" << "fusion";
QProcess *myProcess = new QProcess(parent);
myProcess->start(program, arguments);

"And how to use zip command instead?" - man zip

[SGaist]

Hi,

To add to @jsulm, since you are piping several commands, take a look at setStandardOutputProcess.

[JonB]

@sonichy
You cannot send git ls-files | xargs tar -czvf file.tar.gz to QProcess to execute. You do not intend it to be a single command, it is 2 commands. Any "command" containing tokens such as |, >, <, & etc. cannot in itself be executed as one command. If you try, say, QProcess::execute('ls | cat') you should get messages like:

/usr/bin/ls: cannot access '|': No such file or directory
/usr/bin/ls: cannot access 'cat': No such file or directory

showing the | & cat have been passed as arguments to the ls, which is not what you intended.

You have two choices:

1. Set up multiple QProcesss --- one for the git ls-files, another for the xargs tar -czvf ... --- and connect the output of the first to the input of the second (setStandardOutputProcess()).

2. Wrap your command into a single string to be executed by the shell, which is what processes the | token, e.g.:

process->start("/bin/sh", QStringList() << "-c" << "git ls-files | xargs tar -czvf " + QFileInfo(path).fileName() + ".tar.gz");

You do have be careful that you know the shell quoting rules for the argument passed after -c in this case, yours will probably work as I have shown. This way you have a single command, whose output you can capture in the normal way.

[sonichy]

@SGaist tar.gz solved !

QProcess *process1 = new QProcess;
QProcess *process2 = new QProcess;
process1->setStandardOutputProcess(process2);
process1->setWorkingDirectory(path);
process2->setWorkingDirectory(path);
connect(process1, SIGNAL(readyReadStandardOutput()), this, SLOT(processOutput()));
connect(process1, SIGNAL(readyReadStandardError()), this, SLOT(processError()));
connect(process2, SIGNAL(readyReadStandardOutput()), this, SLOT(processOutput()));
connect(process2, SIGNAL(readyReadStandardError()), this, SLOT(processError()));
process1->start("git ls-files");
process2->start("xargs tar -czvf " + QFileInfo(path).fileName() + ".tar.gz");

[sonichy]

@JonB zip solved !

QProcess *process1 = new QProcess;
process1->setWorkingDirectory(path);
connect(process1, SIGNAL(readyReadStandardError()), this, SLOT(processError()));
process1->start("git ls-files");
process1->waitForFinished();
QString s = QString(process1->readAllStandardOutput()).replace("\n"," ");
qDebug() << s;
s = "zip " + QFileInfo(path).fileName() + ".zip -xi " + s;
qDebug() << s;
connect(process1, SIGNAL(readyReadStandardOutput()), this, SLOT(processOutput()));
process1->start(s);
if(process1->waitForFinished())
    genList(path);