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# Env

- NAME
- SYNOPSIS
- DESCRIPTION
- LIMITATIONS
- AUTHOR

## 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`>

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