Your problem here is that you're actually using two regexes. Interpolating these separately works fine: 

ken@ganymede: ~/tmp
$ cat pm_re2_file.txt
Hello World

--Begin--
Cat
and
Dog
--End--

other stuff 
This is a test
Good Bye
ken@ganymede: ~/tmp
$ RE1="--Begin--" RE2="--End--" perl -00 -ne 'print if /$ENV{RE1}/ && 
+/$ENV{RE2}/' pm_re2_file.txt
--Begin--
Cat
and
Dog
--End--

ken@ganymede: ~/tmp
$

[download]

If you have a specific requirement to use just one environment variable, I'd suggest using eval: 

ken@ganymede: ~/tmp
$ RE1="/--Begin--/ && /--End--/" perl -00 -ne 'print if eval $ENV{RE1}
+' pm_re2_file.txt
--Begin--
Cat
and
Dog
--End--

ken@ganymede: ~/tmp
$

[download]

-- Ken

In reply to Re: Using a regex saved in an environment variable by kcott
in thread Using a regex saved in an environment variable by J0ax88

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.