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.\" -*- mode: troff; coding: utf-8 -*- .\" Automatically generated by Pod::Man 5.01 (Pod::Simple 3.43) .\" .\" 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 .. .\" \*(C` and \*(C' are quotes in nroff, nothing in troff, for use with C<>. .ie n \{\ . ds C` "" . ds C' "" 'br\} .el\{\ . ds C` . ds C' 'br\} .\" .\" Escape single quotes in literal strings from groff's Unicode transform. .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" .\" If the F register is >0, we'll generate index entries on stderr for .\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index .\" entries marked with X<> in POD. Of course, you'll have to process the .\" output yourself in some meaningful fashion. .\" .\" Avoid warning from groff about undefined register 'F'. .de IX .. .nr rF 0 .if \n(.g .if rF .nr rF 1 .if (\n(rF:(\n(.g==0)) \{\ . if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} . \} .\} .rr rF .\" ======================================================================== .\" .IX Title "Env 3" .TH Env 3 2023-05-26 "perl v5.38.0" "Perl Programmers Reference Guide" .\" For nroff, turn off justification. 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($SHELL @LD_LIBRARY_PATH); .Ve .SH DESCRIPTION .IX Header "DESCRIPTION" Perl maintains environment variables in a special hash named \f(CW%ENV\fR. For when this access method is inconvenient, the Perl module \f(CW\*(C`Env\*(C'\fR allows environment variables to be treated as scalar or array variables. .PP The \f(CWEnv::import()\fR function ties environment variables with suitable names to global Perl variables with the same names. By default it ties all existing environment variables (\f(CW\*(C`keys %ENV\*(C'\fR) to scalars. If the \f(CW\*(C`import\*(C'\fR function receives arguments, it takes them to be a list of variables to tie; it's okay if they don't yet exist. The scalar type prefix '$' 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 .= ":/any/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/any/path\*(Aq; .Ve .PP is almost equivalent to: .PP .Vb 2 \& use Env qw(PATH); \& $PATH .= ":/any/path"; .Ve .PP except that if \f(CW$ENV{PATH}\fR started out empty, the second approach leaves it with the (odd) value "\f(CW\*(C`:/any/path\*(C'\fR", but the first approach leaves it with "\f(CW\*(C`/any/path\*(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 VMS 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>