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The first two elements of the list must be the NUMERIC access and modification times, in that order. Returns the number of files successfully changed. The inode change time of each file is set to the current time. For example, this code has the same effect as the Unix touch(1) command when the files <i>already exist</i> and belong to the user running the program:</p> <pre><code>#!/usr/bin/perl $atime = $mtime = time; utime $atime, $mtime, @ARGV;</code></pre> <p>Since Perl 5.8.0, if the first two elements of the list are <code>undef</code>, the utime(2) syscall from your C library is called with a null second argument. On most systems, this will set the file's access and modification times to the current time (i.e., equivalent to the example above) and will work even on files you don't own provided you have write permission:</p> <pre><code> for $file (@ARGV) { utime(undef, undef, $file) || warn "couldn't touch $file: $!"; } </code></pre> <p>Under NFS this will use the time of the NFS server, not the time of the local machine. If there is a time synchronization problem, the NFS server and local machine will have different times. The Unix touch(1) command will in fact normally use this form instead of the one shown in the first example.</p> <p>Passing only one of the first two elements as <code>undef</code> is equivalent to passing a 0 and will not have the effect described when both are <code>undef</code>. This also triggers an uninitialized warning.</p> <p>On systems that support futimes(2), you may pass filehandles among the files. On systems that don't support futimes(2), passing filehandles raises an exception. Filehandles must be passed as globs or glob references to be recognized; barewords are considered filenames.</p> <p>Portability issues: <a href="/5.18.2/perlport#utime">"utime" in perlport</a>.</p> </dd> </dl> </div> <div id="footer"> <p>Perldoc Browser is maintained by Dan Book (<a href="https://metacpan.org/author/DBOOK">DBOOK</a>). Please contact him via the <a href="https://github.com/Grinnz/perldoc-browser/issues">GitHub issue tracker</a> or <a href="mailto:dbook@cpan.org">email</a> regarding any issues with the site itself, search, or rendering of documentation.</p> <p>The Perl documentation is maintained by the Perl 5 Porters in the development of Perl. 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