System Command QProcess

[jd]

Hello folks,

I'll execute a system command on a Linux maschine. I've created this in a QProcess, but the result was very small.

QString cmd("dpkg");
 
    QProcess* process = new QProcess(this);
    process->start(QFile::encodeName(cmd).data(), QStringList() << "-l" << "| grep" << "xorg");
    process->waitForFinished();
 
    QString tmp = process->readAll();
    qDebug() << tmp;

QString cmd("dpkg");

    QProcess* process = new QProcess(this);
    process->start(QFile::encodeName(cmd).data(), QStringList() << "-l" << "| grep" << "xorg");
    process->waitForFinished();

    QString tmp = process->readAll();
    qDebug() << tmp;

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The return has a length from one line. This is wrong if I type dpgk -l | grep xorg I becomes over 20 Lines.

If I try this:

process->start(QFile::encodeName(cmd).data(), QStringList() << "-l");

process->start(QFile::encodeName(cmd).data(), QStringList() << "-l");

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So, with one argument all works fine, if I had more as one argument, the result ist not correctly.


Can someone tell me how to fix the argument list?

Thanks.

so long
jd

// Sorry wrong forum, can someone move my post.

[jpn]

That's not a single command. You need to launch a shell to interpret the commands. See for example this post.

[jd]

Hello,

I've modified my function, but it doesn't work. I've no result...

QStringList arguments;
    arguments << "-c" << "dpkg" << "-l" << "|" << "grep" << "xorg";
    QProcess* process = new QProcess(this);
    process->start("/bin/sh", arguments);
    process->waitForFinished();
 
    QString tmp = process->readAll();
    qDebug() << tmp;

QStringList arguments;
    arguments << "-c" << "dpkg" << "-l" << "|" << "grep" << "xorg";
    QProcess* process = new QProcess(this);
    process->start("/bin/sh", arguments);
    process->waitForFinished();

    QString tmp = process->readAll();
    qDebug() << tmp;

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I've executed the command in the shell manually and this works fine:

/bin/sh -c "dpkg -l | grep xorg"

So, were is the problem in my code.

so long and thanks for help

jd

[jpn]

Try

arguments << "-c" << "dpkg -l | grep xorg";

arguments << "-c" << "dpkg -l | grep xorg";

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[jd]

Thanks, works fine now.

[talk2amulya]

Hi jpn,

though the query is solved now, i would appreciate it if u tell me why it worked with combining last 5 arguments into one string argument and not otherwise

thanks a heap!

[jpn]

i would appreciate it if u tell me why it worked with combining last 5 arguments into one string argument and not otherwise

Because it's a single argument for /bin/sh. From command line you'd run it like this:

/bin/sh -c "dpkg -l | grep xorg"

/bin/sh -c "dpkg -l | grep xorg"

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not like this:

/bin/sh -c dpkg -l | grep xorg

/bin/sh -c dpkg -l | grep xorg

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Right?

[talk2amulya]

i m gonna hide under my bed..that was so stupid, i should've caught that..thanks jpn!