Fascinating question.

First I tried open OUT, ">> $file" and close OUT but that didn't change the time of the file.

So I thought a bit, and tried open OUT, ">> $file" and print OUT '' and close OUT; but that didn't work either.

You could always do a system '/usr/bin/touch', $file but that requires knowing where your external touch program lies.

Then I read the source code to touch.c, found that it refers to a system call named utimes. Looked up utime in perldoc, and got the answer:

  my $now = time;
  utime $now, $now, $file;

[download]

This changes both the last access time and last modification time to now.

In reply to Re: syntax of touch a file by grinder
in thread syntax of touch a file by hweefarn

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.