QProcess and Pipes

[KaptainKarl]

I'm creating a server monitor and want to get a process table listing of certain processes. My first, and probably incorrect, thought was to create a QProcess and call the UNIX 'ps' command and then parse the standard output.

The following code works fine:
NOTE: The cvtLogger function appends the QString argument to a QTextEdit.
QString sCmd = "ps"; QStringList slArgs; slArgs.append("aux"); QProcess *pServerCheck = new QProcess; pServerCheck->setReadChannelMode(QProcess::MergedChannels); pServerCheck->start(sCmd, slArgs); if (!pServerCheck->waitForFinished()) {
cntlLogger(pServerCheck->errorString()); } else { cntlLogger(pServerCheck->readAll()); } delete pServerCheck;Now, if I try to use a pipe to grep to get just the process I want, it doesn't work.
QString sCmd = "ps";
QStringList slArgs;
slArgs.append("aux");
slArgs.append("| grep SMRTemd");
QProcess *pServerCheck = new QProcess;
pServerCheck->setReadChannelMode(QProcess::MergedChannels);
pServerCheck->start(sCmd, slArgs);
if (!pServerCheck->waitForFinished())
{
cntlLogger(pServerCheck->errorString());
}
else
{
cntlLogger("EMD PID: " + pServerCheck->readAll());
}
delete pServerCheck;The output comes through the "readAll" branch is:
EMD PID: ERROR: Garbage option.I also tried putting "ps aux | grep SMRTemd" into a single QString and passing it to QProcess that way. It returned the same error.

Is there an easier way to do this that I'm not thinking of?

Thanks,

Karl

[jacek]

You are invoking ps with two parameters: "aux" and "| grep SMRTemd". Just as if you wrote:

$ ps aux "| grep SMRTemd"

If you want to make | work, start a shell:

QString sCmd( "/bin/sh" );
QStringList slArgs;
slArgs << "-c" << "ps aux | grep SMRTemd";

QString sCmd( "/bin/sh" );
QStringList slArgs;
slArgs << "-c" << "ps aux | grep SMRTemd";

To copy to clipboard, switch view to plain text mode