Env
Lets your program treat environment variables as simple
variables instead of having to access them from the %ENV pseudo-hash where they are kept. (Note
that pseudo-hashes will disappear as of Perl 6.)
use Env; use Env qw(var1var2...);
Internally, Env uses an import function that ties suitably named
environment variables to global Perl variables with the same names. By
default, it ties all variables yielded by keys %ENV. A “suitable” environment has a
name that begins with an alphabetic character and contains only
alphanumeric characters or underscores.
When use Env is invoked with
arguments, the arguments are interpreted as a list of environment
variables to tie, but the variables
don’t have to exist yet. After a variable has been tied, you can use
it like a normal variable, accessing or changing its value.
You untie a variable by setting its value to undef.