I have a contiuously running script that executes pieces of perl code stored in mysql. I control the input scripts so security and namespace polution are not really a concern, although ideas about controlling that as well are welcome.

I currently write out what I want STDIN to be to a file, and the reassign STDIN to that file, restoring STDIN when done. Same goes for STDERR and STDOUT.

open(SAVEOUT, ">&STDOUT");
open(SAVEERR, ">&STDERR");
close(STDIN);
open(STDIN, $stdin_file);
close(STDOUT);
open(STDOUT,'>' . $stdout_file);
close(STDERR);
open(STDERR,'>' . $stderr_file);
select(STDERR); $| = 1;
select(STDOUT); $| = 1;
eval $perl_script_content;
my $result_code = $@;

[download]

Works, but now I have to read the files back in to get the results, and files are so passe.

Is there a direct way to redirect what would go to STDOUT and STDERR to variables, for the purpose of catching the output of my eval? I imagine the same could be used to redirect my STDIN from a variable.

I'm using an eval to avoid invoking the shell. I do want the perl code that is to be run to work standalone though, so no rewriting it as a sub.

I've seen working examples using a double fork, but that seems excessive.

Thank you Monks,

In reply to Reassign STDOUT/STDERR contents to a variable by lothos

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.