replace line of a file

[ChrisW67]

Nothing to do with Qt per se. General steps:

• Open original file for reading
• Open temporary file for writing
• Write lines from original file until you reach the line you want to replace
• Write the replacement line
• Skip the line from the original file
• Write lines from original file until end of file
• Close temporary and original file
• If all of above successful, remove original file and copy/rename temporary file.

Start with QFile, QTextStream and QTemporaryFile in the Qt docs. The temporary file could be in-memory; see QBuffer.