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RedHat 9 (Linux i386) - man page for env (redhat section 3pm)

Env(3pm)				   Perl Programmers Reference Guide				     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($SHELL @LD_LIBRARY_PATH);
DESCRIPTION
Perl maintains environment variables in a special hash named %ENV. For when this access method is inconve- nient, the Perl module "Env" allows environment variables to be treated as scalar or array variables. The "Env::import()" function ties environment variables with suitable names to global Perl variables with the same names. By default it ties all existing environment variables ("keys %ENV") to scalars. If the "import" function receives arguments, it takes them to be a list of variables to tie; it's okay if they don't yet exist. The scalar type prefix '$' 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> perl v5.8.0 2002-06-01 Env(3pm)


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