You will need to do two things. First, capture the return value of $fs->Show into a variable (i.e. my $dir = $fs->Show;. Then, use associate that variable with the entry widget. The Entry widget has a property called "-textvariable". By setting that to the variable that captures the user's input from the File Select (-textvariable => \$dir), the value of the Entry widget will reflect any changes in that variable.