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  4. why QProcess not show output of ls /dev/sd* command ?
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why QProcess not show output of ls /dev/sd* command ?

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  • jsulmJ jsulm

    @Qt-embedded-developer said in why QProcess not show output of ls /dev/sd* command ?:

    can you let me know how i can get absolute path ?

    Execute the bellow command:
    which ls

    JonBJ Online
    JonBJ Online
    JonB
    wrote on last edited by JonB
    #7

    @jsulm said in why QProcess not show output of ls /dev/sd* command ?:

    which ls

    Observation: if which finds ls then there is no need to use a full path to it. And if it's not on your path which won't find it! :)

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    • jsulmJ jsulm

      @Qt-embedded-developer said in why QProcess not show output of ls /dev/sd* command ?:

      i think its not relative path this is absolute path

      How is ls an absolute path?!
      On my Ubuntu machine the absolute path to ls is /usr/bin/ls

      I'm wondering why you need QProcess for such a task at all? You can simply use https://doc.qt.io/qt-6/qdir.html

      Q Offline
      Q Offline
      Qt embedded developer
      wrote on last edited by
      #8

      @jsulm means i just need to check there is file name start with sd is there on not int /dev directory

      jsulmJ 1 Reply Last reply
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      • JonBJ JonB

        @Qt-embedded-developer
        Because your /dev/sd* has a * wildcard in it. ls (or any other Linux command) does not expand wildcards. Only a shell expands wildcards! If you want to do it this way you will need:

         Command = "/bin/sh";
        
        args << "-c" << "ls /dev/sd*";
        

        Note that running a command to expand a filepath like this is not "efficient". You could do the work from, say, Qt QDir on /dev and look through the child filenames yourself to see which start with sd. Or QFileInfoList QDir::entryInfoList(const QStringList &nameFilters, QDir::Filters filters = NoFilter, QDir::SortFlags sort = NoSort) const could be used to do the wildcard matching. This would also be a lot cleaner than your code trying to parse ls's output.

        Q Offline
        Q Offline
        Qt embedded developer
        wrote on last edited by
        #9

        @JonB said in why QProcess not show output of ls /dev/sd* command ?:

        QFileInfoList QDir::entryInfoList(const QStringList &nameFilters, QDir::Filters filters = NoFilter, QDir::SortFlags sort = NoSort) const

        as per my case what i need to write in above ?

        jsulmJ 1 Reply Last reply
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        • Q Qt embedded developer

          @jsulm means i just need to check there is file name start with sd is there on not int /dev directory

          jsulmJ Offline
          jsulmJ Offline
          jsulm
          Lifetime Qt Champion
          wrote on last edited by
          #10

          @Qt-embedded-developer Yes, get entries in /dev folder using QDir::entryInfoList and filter all entries starting with sd (you can pass file name filter directly to QDir::entryInfoList).

          https://forum.qt.io/topic/113070/qt-code-of-conduct

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          • Q Qt embedded developer

            @JonB said in why QProcess not show output of ls /dev/sd* command ?:

            QFileInfoList QDir::entryInfoList(const QStringList &nameFilters, QDir::Filters filters = NoFilter, QDir::SortFlags sort = NoSort) const

            as per my case what i need to write in above ?

            jsulmJ Offline
            jsulmJ Offline
            jsulm
            Lifetime Qt Champion
            wrote on last edited by
            #11

            @Qt-embedded-developer said in why QProcess not show output of ls /dev/sd* command ?:

            as per my case what i need to write in above ?

            What exactly is not clear?

            https://forum.qt.io/topic/113070/qt-code-of-conduct

            Q 1 Reply Last reply
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            • jsulmJ jsulm

              @Qt-embedded-developer said in why QProcess not show output of ls /dev/sd* command ?:

              as per my case what i need to write in above ?

              What exactly is not clear?

              Q Offline
              Q Offline
              Qt embedded developer
              wrote on last edited by Qt embedded developer
              #12

              @jsulm sorry its clear. i have to try. but if possible can you give example so it can help better.

              Christian EhrlicherC 1 Reply Last reply
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              • Q Qt embedded developer

                @jsulm sorry its clear. i have to try. but if possible can you give example so it can help better.

                Christian EhrlicherC Offline
                Christian EhrlicherC Offline
                Christian Ehrlicher
                Lifetime Qt Champion
                wrote on last edited by
                #13

                @Qt-embedded-developer said in why QProcess not show output of ls /dev/sd* command ?:

                but if possible can you give example so it can help better.

                Maybe reading the answers would help - it was already given...

                Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
                Visit the Qt Academy at https://academy.qt.io/catalog

                Q 1 Reply Last reply
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                • Christian EhrlicherC Christian Ehrlicher

                  @Qt-embedded-developer said in why QProcess not show output of ls /dev/sd* command ?:

                  but if possible can you give example so it can help better.

                  Maybe reading the answers would help - it was already given...

                  Q Offline
                  Q Offline
                  Qt embedded developer
                  wrote on last edited by Qt embedded developer
                  #14

                  @Christian-Ehrlicher i have tried like below but i am getting empty list from fileinfolist

                  QString myPath="/dev";
                          QDir dir;
                          dir.setPath(myPath);
                          QStringList filters;
                          filters<<"sd";
                          dir.setFilter( QDir::AllEntries | QDir::System);
                          dir.setNameFilters(filters);
                          dir.setSorting(QDir::Name );
                          QFileInfoList list = dir.entryInfoList();
                  
                  

                  why my list is not giving file name what is expected ?

                  JonBJ 1 Reply Last reply
                  0
                  • Christian EhrlicherC Offline
                    Christian EhrlicherC Offline
                    Christian Ehrlicher
                    Lifetime Qt Champion
                    wrote on last edited by
                    #15

                    Because there is no /dev/sd in your directory. Please read the documentation...

                    Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
                    Visit the Qt Academy at https://academy.qt.io/catalog

                    Q 1 Reply Last reply
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                    • Christian EhrlicherC Christian Ehrlicher

                      Because there is no /dev/sd in your directory. Please read the documentation...

                      Q Offline
                      Q Offline
                      Qt embedded developer
                      wrote on last edited by
                      #16

                      @Christian-Ehrlicher actually above code i written to find name that start with sd .

                      Christian EhrlicherC 1 Reply Last reply
                      0
                      • Q Qt embedded developer

                        @Christian-Ehrlicher actually above code i written to find name that start with sd .

                        Christian EhrlicherC Offline
                        Christian EhrlicherC Offline
                        Christian Ehrlicher
                        Lifetime Qt Champion
                        wrote on last edited by Christian Ehrlicher
                        #17

                        @Qt-embedded-developer said in why QProcess not show output of ls /dev/sd* command ?:

                        actually above code i written to find name that start with sd .

                        No, RTFM!

                        Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
                        Visit the Qt Academy at https://academy.qt.io/catalog

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                        • Q Qt embedded developer

                          @Christian-Ehrlicher i have tried like below but i am getting empty list from fileinfolist

                          QString myPath="/dev";
                                  QDir dir;
                                  dir.setPath(myPath);
                                  QStringList filters;
                                  filters<<"sd";
                                  dir.setFilter( QDir::AllEntries | QDir::System);
                                  dir.setNameFilters(filters);
                                  dir.setSorting(QDir::Name );
                                  QFileInfoList list = dir.entryInfoList();
                          
                          

                          why my list is not giving file name what is expected ?

                          JonBJ Online
                          JonBJ Online
                          JonB
                          wrote on last edited by
                          #18

                          @Qt-embedded-developer said in why QProcess not show output of ls /dev/sd* command ?:

                          filters<<"sd";

                          void QDir::setNameFilters(const QStringList &nameFilters)

                          Each name filter is a wildcard (globbing) filter that understands * and ? wildcards. See QRegularExpression::fromWildcard().

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