env(3pm)

NAME

Env - perl module that imports environment variables as scalars or
arrays

SYNOPSIS

use Env;
use Env qw(PATH HOME TERM);
use Env qw($SHELL @LD_LIBRARY_PATH);

DESCRIPTION

Perl maintains environment variables in a special hash named %ENV. For when this access method is inconvenient, the Perl module "Env" allows
environment variables to be treated as scalar or array variables.

The "Env::import()" function ties environment variables with suitable
names to global Perl variables with the same names. By default it ties all existing environment variables ("keys %ENV") to scalars. If the
"import" function receives arguments, it takes them to be a list of
variables to tie; it's okay if they don't yet exist. The scalar type
prefix '$' is inferred for any element of this list not prefixed by '$' or '@'. Arrays are implemented in terms of "split" and "join", using
$Config::Config{path_sep} as the delimiter.

After an environment variable is tied, merely use it like a normal variable. You may access its value: @path = split(/:/, $PATH);
print join("\n", @LD_LIBRARY_PATH), "\n";
or modify it: $PATH .= ":.";
push @LD_LIBRARY_PATH, $dir;
however you'd like. Bear in mind, however, that each access to a tied array variable requires splitting the environment variable's string anew.
The code:: use Env qw(@PATH);
push @PATH, '.';
is equivalent to:: use Env qw(PATH);
$PATH .= ":.";
except that if $ENV{PATH} started out empty, the second approach leaves it with the (odd) value "":."", but the first approach leaves it with ""."".
To remove a tied environment variable from the environment, assign it the undefined value: undef $PATH;
undef @LD_LIBRARY_PATH;

LIMITATIONS

On VMS systems, arrays tied to environment variables are read-only.
Attempting to change anything will cause a warning.

AUTHOR

Chip Salzenberg <chip@fin.uucp> and Gregor N. Purdy <gregor@focusresearch.com>

docs.sk