# phpman > man > 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](https://www.chedong.com/phpMan.php/perldoc/Env%3A%3Aimport/markdown)()" 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](https://www.chedong.com/phpMan.php/perldoc/Config%3A%3AConfig/markdown){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 .= ":/any/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, '/any/path';

    is almost equivalent to:

        use Env qw(PATH);
        $PATH .= ":/any/path";

    except that if $ENV{PATH} started out empty, the second approach leaves it with the (odd) value
    "":/any/path"", but the first approach leaves it with ""/any/path"".

    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>>