All contributions dictatorially edited by webmasters to match personal tastes.
Please do not paste any copyright violating resource.
Please try to avoid dependencies to third-party libraries and frameworks.
use Path::Tiny qw(path);
my $F = path('F')->openrw; # ... read some from $F to advance # position of file handle (not shown) ... truncate $F, tell $F;
var F = new FileStream("F", FileMode.Open) // advance into F here F.SetLength(F.Position);