.\" Automatically generated by Pod::Man 2.28 (Pod::Simple 3.28) .\" .\" Standard preamble: .\" ======================================================================== .de Sp \" Vertical space (when we can't use .PP) .if t .sp .5v .if n .sp .. .de Vb \" Begin verbatim text .ft CW .nf .ne \\$1 .. .de Ve \" End verbatim text .ft R .fi .. .\" Set up some character translations and predefined strings. \*(-- will .\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left .\" double quote, and \*(R" will give a right double quote. \*(C+ will .\" give a nicer C++. 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Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH "NAME" Env \- perl module that imports environment variables as scalars or arrays .SH "SYNOPSIS" .IX Header "SYNOPSIS" .Vb 3 \& use Env; \& use Env qw(PATH HOME TERM); \& use Env qw($SHELL @LD_LIBRARY_PATH); .Ve .SH "DESCRIPTION" .IX Header "DESCRIPTION" Perl maintains environment variables in a special hash named \f(CW%ENV\fR. For when this access method is inconvenient, the Perl module \f(CW\*(C`Env\*(C'\fR allows environment variables to be treated as scalar or array variables. .PP The \f(CW\*(C`Env::import()\*(C'\fR function ties environment variables with suitable names to global Perl variables with the same names. By default it ties all existing environment variables (\f(CW\*(C`keys %ENV\*(C'\fR) to scalars. If the \f(CW\*(C`import\*(C'\fR function receives arguments, it takes them to be a list of variables to tie; it's okay if they don't yet exist. The scalar type prefix '$' is inferred for any element of this list not prefixed by '$' or '@'. Arrays are implemented in terms of \f(CW\*(C`split\*(C'\fR and \f(CW\*(C`join\*(C'\fR, using \&\f(CW$Config::Config{path_sep}\fR as the delimiter. .PP After an environment variable is tied, merely use it like a normal variable. You may access its value .PP .Vb 2 \& @path = split(/:/, $PATH); \& print join("\en", @LD_LIBRARY_PATH), "\en"; .Ve .PP or modify it .PP .Vb 2 \& $PATH .= ":."; \& push @LD_LIBRARY_PATH, $dir; .Ve .PP however you'd like. Bear in mind, however, that each access to a tied array variable requires splitting the environment variable's string anew. .PP The code: .PP .Vb 2 \& use Env qw(@PATH); \& push @PATH, \*(Aq.\*(Aq; .Ve .PP is equivalent to: .PP .Vb 2 \& use Env qw(PATH); \& $PATH .= ":."; .Ve .PP except that if \f(CW$ENV{PATH}\fR started out empty, the second approach leaves it with the (odd) value "\f(CW\*(C`:.\*(C'\fR\*(L", but the first approach leaves it with \*(R"\f(CW\*(C`.\*(C'\fR". .PP To remove a tied environment variable from the environment, assign it the undefined value .PP .Vb 2 \& undef $PATH; \& undef @LD_LIBRARY_PATH; .Ve .SH "LIMITATIONS" .IX Header "LIMITATIONS" On \s-1VMS\s0 systems, arrays tied to environment variables are read-only. Attempting to change anything will cause a warning. .SH "AUTHOR" .IX Header "AUTHOR" Chip Salzenberg <\fIchip@fin.uucp\fR> and Gregor N. Purdy <\fIgregor@focusresearch.com\fR>