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Linux系统下qt防止同一程序在系统中运行两个实例，直接上代码：
QEventLoop loop;
connect(&process,SIGNAL(readyReadStandardOutput()),&loop,SLOT(quit()));
QStringList args;
args<<"-c";
args<<"ps -e|grep '实例名称'";
process.start("sh",args);
loop.exec();
QByteArray vTemp = process.readAllStandardOutput();if(vTemp.count(" 实例名称")>1){
showTipDialog("程序已运行!");
exit(0);
}