|blib(3perl)||Perl Programmers Reference Guide||blib(3perl)|
perl -Mblib script [args...] perl -Mblib=dir script [args...]
Intended for use on command line with -M option as a way of testing arbitrary scripts against an uninstalled version of a package.
However it is possible to :
use blib; or use blib '..';
etc. if you really must.