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Env (3)
  • Env (3) ( Solaris man: Библиотечные вызовы )
  • >> Env (3) ( Разные man: Библиотечные вызовы )
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    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 <[email protected]> and Gregor N. Purdy <[email protected]>


     

    Index

    NAME
    SYNOPSIS
    DESCRIPTION
    LIMITATIONS
    AUTHOR


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