.\" Automatically generated by Pod::Man 2.27 (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++. Capital omega is used to do unbreakable dashes and
.\" therefore won't be available. \*(C` and \*(C' expand to `' in nroff,
.\" nothing in troff, for use with C<>.
.tr \(*W-
.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
.ie n \{\
. ds -- \(*W-
. ds PI pi
. if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
. if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch
. ds L" ""
. ds R" ""
. ds C` ""
. ds C' ""
'br\}
.el\{\
. ds -- \|\(em\|
. ds PI \(*p
. ds L" ``
. ds R" ''
. 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 turned on, 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 "2013-03-02" "perl v5.16.3" "User Contributed Perl Documentation"
.\" 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($SHELL @LD_LIBRARY_PATH);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
Perl maintains environment variables in a special hash named \f(CW%ENV\fR. For
when this access method is inconvenient, the Perl module \f(CW\*(C`Env\*(C'\fR allows
environment variables to be treated as scalar or array variables.
.PP
The \f(CW\*(C`Env::import()\*(C'\fR function ties environment variables with suitable
names to global Perl variables with the same names. By default it
ties all existing environment variables (\f(CW\*(C`keys %ENV\*(C'\fR) to scalars. If
the \f(CW\*(C`import\*(C'\fR function receives arguments, it takes them to be a list of
variables to tie; it's okay if they don't yet exist. The scalar type
prefix '$' 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>