Your post is a little confusing and not well formatted (HTML can be a bi+<# ).

I have interpreted your post that your config file really contains the following string:

Id = $ENV{APPL}

[download]
Why using perl syntax here?

I also assume that the file and its lines got already parsed so you end up with a variable holding the string '$ENV{APPL}'. You could simply eval this string: 

$string = '$ENV{APPL}';
$var =  eval $string;

[download]
However, this is very dangerous because the config file could also hold any other Perl code there, e.g. code which deletes your complete hard drive.

Therefore it is safer to extract the 'APPL' part using a regular expression: 

if ($string =~ /\$ENV{([^}]+)}/) {
  $var = $ENV{$1};
}

[download]
The regular expression could also be /\$ENV\s*{\s*(.*?)\s*}$/ to allow for spaces before and after the braces.

I hope this is what you wanted.

In reply to Re: expanding Environment variable by mscharrer
in thread expanding Environment variable by Sun751

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.