If phimtau123 is on a *nixy system he could dig in `lsof`s output with (e)grep

Well, if he were on a UNIX system he wouldn't need to do that at all, because POSIX-compliant systems allow you to unlink files while they are being held open by another process, the process can continue reading/writing to the unlinked file but the file ceases to exist once the filehandle is closed. Also, greping lsof output for a filename is insanely wasteful, because it makes lsof pipe all the filenames of open files on the entire system to grep, which then throws most of them away. Instead, just do