env(3)

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 vari
ables ("keys %ENV") to scalars. If the "import" function
receives arguments, it takes them to be a list of vari
ables 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::Con
fig{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("0, @LD_LIBRARY_PATH), "0;
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 environ ment, 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 <gre_ gor@focusresearch.com>

docs.sk