slackbuilds_ponce/perl/perl-PerlIO-Layers

PerlIO::Layers (Perl module)

Perl's filehandles are implemented as a stack of layers, with 
the bottom-most usually doing the actual IO and the higher ones 
doing buffering, encoding/decoding or transformations. 

PerlIO::Layers allows you to query the filehandle's properties 
concerning these layers.