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<html><head><title>Changing Ownership (Learning Perl, 3rd Edition)</title><link rel="stylesheet" type="text/css" href="../style/style1.css" /><meta name="DC.Creator" content="Randal L. Schwartz and Tom Phoenix" /><meta name="DC.Format" content="text/xml" scheme="MIME" /><meta name="DC.Language" content="en-US" /><meta name="DC.Publisher" content="O'Reilly & Associates, Inc." /><meta name="DC.Source" scheme="ISBN" content="0596001320L" /><meta name="DC.Subject.Keyword" content="stuff" /><meta name="DC.Title" content="Learning Perl, 3rd Edition" /><meta name="DC.Type" content="Text.Monograph" /></head><body bgcolor="#ffffff"><img alt="Book Home" border="0" src="gifs/smbanner.gif" usemap="#banner-map" /><map name="banner-map"><area shape="rect" coords="1,-2,616,66" href="index.htm" alt="Learning Perl, 3rd Edition" /><area shape="rect" coords="629,-11,726,25" href="jobjects/fsearch.htm" alt="Search this book" /></map><div class="navbar"><table width="684" border="0"><tr><td align="left" valign="top" width="228"><a href="ch13_05.htm"><img alt="Previous" border="0" src="../gifs/txtpreva.gif" /></a></td><td align="center" valign="top" width="228"><a href="index.htm"></a></td><td align="right" valign="top" width="228"><a href="ch13_07.htm"><img alt="Next" border="0" src="../gifs/txtnexta.gif" /></a></td></tr></table></div><h2 class="sect1">13.6. Changing Ownership</h2><p>If the operating system permits it, you may change the ownership andgroup membership of a list of<a name="INDEX-919" />files with the<tt class="literal">chown</tt><a name="INDEX-920" /> function. The user and group are bothchanged at once, and both have to be the<a name="INDEX-921" />numeric user-ID and<a name="INDEX-922" />group-ID values. Forexample:</p><blockquote><pre class="code">my $user = 1004;my $group = 100;chown $user, $group, glob "*.o";</pre></blockquote><p>What if you have a username like <tt class="literal">merlyn</tt> instead ofthe number? Simple. Just call the<tt class="literal">getpwnam</tt><a name="INDEX-923" /> function to translate the name into anumber, and the corresponding <tt class="literal">getgrnam<a href="#FOOTNOTE-297">[297]</a></tt><a name="INDEX-924" /> to translate the group name into itsnumber:</p><blockquote class="footnote"><a name="FOOTNOTE-297" /><p>[297]These two are among the ugliest function names known tomankind. But don't blame Larry for them; he's just givingthem the same names that the folks at Berkeley did. </p></blockquote><blockquote><pre class="code">defined(my $user = getpwnam "merlyn") or die "bad user";defined(my $group = getgrnam "users") or die "bad group";chown $user, $group, glob "/home/merlyn/*";</pre></blockquote><p>The <tt class="literal">defined</tt><a name="INDEX-925" /> function verifies that the returnvalue is not <tt class="literal">undef</tt>, which will be returned if therequested user or group is not valid.</p><p>The <tt class="literal">chown</tt> function returns the number of filesaffected, and it sets <tt class="literal">$!</tt> on error.</p><hr width="684" align="left" /><div class="navbar"><table width="684" border="0"><tr><td align="left" valign="top" width="228"><a href="ch13_05.htm"><img alt="Previous" border="0" src="../gifs/txtpreva.gif" /></a></td><td align="center" valign="top" width="228"><a href="index.htm"><img alt="Home" border="0" src="../gifs/txthome.gif" /></a></td><td align="right" valign="top" width="228"><a href="ch13_07.htm"><img alt="Next" border="0" src="../gifs/txtnexta.gif" /></a></td></tr><tr><td align="left" valign="top" width="228">13.5. Modifying Permissions</td><td align="center" valign="top" width="228"><a href="index/index.htm"><img alt="Book Index" border="0" src="../gifs/index.gif" /></a></td><td align="right" valign="top" width="228">13.7. Changing Timestamps</td></tr></table></div><hr width="684" align="left" /><img alt="Library Navigation Links" border="0" src="../gifs/navbar.gif" usemap="#library-map" /><p><p><font size="-1"><a href="copyrght.htm">Copyright © 2002</a> O'Reilly & Associates. All rights reserved.</font></p><map name="library-map"><area shape="rect" coords="1,0,85,94" href="../index.htm"><area shape="rect" coords="86,1,178,103" href="../lwp/index.htm"><area shape="rect" coords="180,0,265,103" href="../lperl/index.htm"><area shape="rect" coords="267,0,353,105" href="../perlnut/index.htm"><area shape="rect" coords="354,1,446,115" href="../prog/index.htm"><area shape="rect" coords="448,0,526,132" href="../tk/index.htm"><area shape="rect" coords="528,1,615,119" href="../cookbook/index.htm"><area shape="rect" coords="617,0,690,135" href="../pxml/index.htm"></map></body></html>⌨️ 快捷键说明
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