This chapter covers reading and writing files, traversing the file system, and interacting with external programs.
Qt's QDataStream and QTextStream classes make it simple to read and write files. These classes take care of issues such as byte ordering and text encodings, ensuring that Qt applications running on different platforms can read and write each other's files.
Many applications need to traverse directories or get information about a file. Qt's QDir and QFileInfo classes makes this possible.
In some situations, it is necessary to run external programs from within a GUI program. Qt's QProcess class allows us to execute external programs asynchronously, keeping the GUI responsive, with signals to tell us how the execution is progressing.