a more sensible way to change directories
Perl's 'chdir()' has the unfortunate problem of being very, very, very
global. If any part of your program calls 'chdir()' or if any library you
use calls 'chdir()', it changes the current working directory for the
File::chdir gives you an alternative, '$CWD' and '@CWD'. These two
variables combine all the power of 'chdir()', the File::Spec manpage and
the Cwd manpage.