Execute system command from QProcess

[graciano]

Hi,
I was writing a small piece of code to execute some system commands.
I'm using Debian, i changed GDM3 to allow root access (no security issues needed in this case) and the code is:

void criarWindowsDialog::on_pushButton_2_clicked()
{
    ui->commandTextEdit->append("Processo iniciado ...");
    QProcess processo;
    QString comando;
    QStringList args;
    QString fullCommand;
    QString stdOut;
    QString stdError;
 
    //comando 1 - limpar a pasta
    comando = "rm";
    args.clear();
    args<<"-f"<<"/home/srp/imagens/windows/*";
    fullCommand = comando;
    for(int i = 0; i < args.count(); i++)
        fullCommand += " " + args.at(i);
    processo.start(comando,args,QIODevice::ReadOnly);
    processo.waitForFinished();
    stdOut = processo.readAllStandardOutput();
    stdError = processo.readAllStandardError();
    ui->commandTextEdit->append(fullCommand);
    ui->stdOutTextEdit->append(stdOut);
    ui->stdErrorTextEdit->append(stdError);

void criarWindowsDialog::on_pushButton_2_clicked()
{
    ui->commandTextEdit->append("Processo iniciado ...");
    QProcess processo;
    QString comando;
    QStringList args;
    QString fullCommand;
    QString stdOut;
    QString stdError;

    //comando 1 - limpar a pasta
    comando = "rm";
    args.clear();
    args<<"-f"<<"/home/srp/imagens/windows/*";
    fullCommand = comando;
    for(int i = 0; i < args.count(); i++)
        fullCommand += " " + args.at(i);
    processo.start(comando,args,QIODevice::ReadOnly);
    processo.waitForFinished();
    stdOut = processo.readAllStandardOutput();
    stdError = processo.readAllStandardError();
    ui->commandTextEdit->append(fullCommand);
    ui->stdOutTextEdit->append(stdOut);
    ui->stdErrorTextEdit->append(stdError);

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When i check the message from "stdError" i get:

Failed to open terminal.TERM environment variable needs set.

Failed to open terminal.TERM environment variable needs set.

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This is a simple command to delete files inside a folder.
Is the problem related to configuration in debian?

[anda_skoa]

Hmm, strange, rm does't sounds like a program that needs a terminal.

Anyway, set the TERM environment variable as suggested, see QProcess::setProcessEnvironment().

In that particular case, removing files, you could also do that directly.

Cheers,
_

[graciano]

The same thing happens when i try ...

comando = "partimage";
    args.clear();
    args<<"-z1"<<"-o"<<"-d"<<"-b"<<"-save"<<"/dev/sda1 /home/srp/imagens/windows/windows.gz";
    fullCommand = comando;
    for(int i = 0; i < args.count(); i++)
        fullCommand += " " + args.at(i);
    processo.start(comando,args,QIODevice::ReadOnly);
    processo.waitForFinished();
    stdOut = processo.readAllStandardOutput();
    stdError = processo.readAllStandardError();
    ui->commandTextEdit->append(fullCommand);
    ui->stdOutTextEdit->append(stdOut);
    ui->stdErrorTextEdit->append(stdError);

comando = "partimage";
    args.clear();
    args<<"-z1"<<"-o"<<"-d"<<"-b"<<"-save"<<"/dev/sda1 /home/srp/imagens/windows/windows.gz";
    fullCommand = comando;
    for(int i = 0; i < args.count(); i++)
        fullCommand += " " + args.at(i);
    processo.start(comando,args,QIODevice::ReadOnly);
    processo.waitForFinished();
    stdOut = processo.readAllStandardOutput();
    stdError = processo.readAllStandardError();
    ui->commandTextEdit->append(fullCommand);
    ui->stdOutTextEdit->append(stdOut);
    ui->stdErrorTextEdit->append(stdError);

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... only now i'm executing "partimage".
I used QProcess::setProcessEnvironment() to set TERM=xterm but i get the same errors.

By the way, the QProcess::setProcessEnvironment() is labeled as depretated. What does it mean? Not to use??

[anda_skoa]

setEnvironment() is deprecated, setProcessEnvironment is not.

Try to execute something simple that evaluates the TERM variable, e.g.

echo $TERM

Does this give the correct result?

Cheers,
_

[graciano]

I tried this:

env.insert("TERM", "xterm");
processo.setProcessEnvironment(env);
 
//comando 1 - limpar a pasta
comando = "echo";
args.clear();
args<<"$TERM";
fullCommand = comando;
for(int i = 0; i < args.count(); i++)
    fullCommand += " " + args.at(i);
processo.start(comando,args,QIODevice::ReadOnly);
processo.waitForFinished();
stdOut = processo.readAllStandardOutput();
stdError = processo.readAllStandardError();
ui->commandTextEdit->append(fullCommand);
ui->stdOutTextEdit->append(stdOut);
ui->stdErrorTextEdit->append(stdError);

env.insert("TERM", "xterm");
processo.setProcessEnvironment(env);

//comando 1 - limpar a pasta
comando = "echo";
args.clear();
args<<"$TERM";
fullCommand = comando;
for(int i = 0; i < args.count(); i++)
    fullCommand += " " + args.at(i);
processo.start(comando,args,QIODevice::ReadOnly);
processo.waitForFinished();
stdOut = processo.readAllStandardOutput();
stdError = processo.readAllStandardError();
ui->commandTextEdit->append(fullCommand);
ui->stdOutTextEdit->append(stdOut);
ui->stdErrorTextEdit->append(stdError);

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Using a system console i get:

root@srp:~# echo $TERM
xterm

root@srp:~# echo $TERM
xterm

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Using my code, in the ui->stdOutTextEdit e read:

$TERM

$TERM

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[anda_skoa]

Right, sorry, echo $TERM won't work because there is no shell expanding $TERM.

You could try with a simple shell script as the command, no args needed

#!/bin/sh
echo $TERM

#!/bin/sh
echo $TERM

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Cheers,
_

[graciano]

Using a shell script i get the expected output:

comando = "bash";
args.clear();
args<<"/home/srp/imagens/scripts/criarwindows.sh";

comando = "bash";
args.clear();
args<<"/home/srp/imagens/scripts/criarwindows.sh";

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Where does it lead us?