CONTENTS

• 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 .= ":/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>

Perldoc Browser is maintained by Dan Book (DBOOK). Please contact him via the GitHub issue tracker or email regarding any issues with the site itself, search, or rendering of documentation.

The Perl documentation is maintained by the Perl 5 Porters in the development of Perl. Please contact them via the Perl issue tracker, the mailing list, or IRC to report any issues with the contents or format of the documentation.