If you change the permissions on the cgi program with 
chmod +s my_program_name.pl

[download]
and you are the owner, which you can set with 
chown my_user_name my_program_name.pl

[download]
and then you add this sort of thing to the cgi where you work with the file: 
($<,$>)=($>,$<);   # Swap effective and actual user ID
open(FILE, ">>/tmp/myfile") or die "Can't open /tmp/myfile";
print FILE "stuff";
close(FILE);
($>,$<)=($<,$>);   # Swap effective and actual user ID

[download]
it will write the file with your user id, swapping back and forth between the 'nobody' user id and your user id.

Suid programs are usually not used because of security reasons. You should learn about the perl concept of 'taint' in order to get started on learning about cgi security.

Update: fixed a few typos

It should work perfectly the first time! - toma

In reply to Re: File Protections by toma
in thread File Protections by Anonymous Monk

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.