A small snippet on how to create a unique filename in a directory possibly shared over the network between several processes.

This code protects your code against unvoluntarily creating two (temporary) files that get the same name. It does not shield you from malicious race conditions, like another program explicitly creating a file with the same name you chose.

We use the following items to ensure uniqueness down to the level of one second. This means that, unless your machine reissues the same process ID within 1 second, the code will return unique filenames.

Update :In another post by ybiC, I saw the mention of Sys::HostIP, which tries harder than Sys::Hostname to find the hostname of a machine. So maybe it would be useful in this snippet, but it is not in the Perl standard distribution.

A one liner : 
perl -MSys::Hostname -we 'print( hostname() . ".$$." . time() . ".tmp"
+, "\n")'

[download]
A function : 
  require Sys::Hostname;

  sub uniqueFilename() {
    my $processName;
    $processName = shift || "tmp";
    return $processName . "." . hostname() . ".$$." . time() . ".tmp";
  };

[download]

In reply to Unique filenames in a shared directory (The Kitchensink) by Corion

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.