in reply to Re^2: overwrite a file
in thread overwrite a file

Bottomline: Solid erasure of data on a granular level like files is always tricky.
Agreed. However, secure shredding on disk level is less tricky, albeit cumbersome, as seen here.
--
print map{chr}unpack(q{A3}x24,q{074117115116032097110111116104101114032080101114108032104097099107101114})

In Section Cool Uses for Perl