The opendir function works like the C and C++ library call of the same name. You give it the name of a new directory handle and a string value denoting the name of the directory to be opened. The return value from opendir is true if the directory can be opened, false otherwise. Here's an example:
opendir(ETC,"/etc") || die "Cannot opendir /etc: $!";
Normally, at this point, we'd go playing with the directory handle ETC, but it's probably nice to know how to close the directory handle first. This is done with closedir, in a similar manner to using close, like so:
closedir(ETC);
Like close, closedir is often unnecessary, since all directory handles are automatically closed before they're reopened or at the end of the program.