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<HTML><!--Distributed by F --><HEAD><TITLE>[Chapter 22] 22.3 Who Will Own a New File? </TITLE><METANAME="DC.title"CONTENT="UNIX Power Tools"><METANAME="DC.creator"CONTENT="Jerry Peek, Tim O'Reilly &amp; Mike Loukides"><METANAME="DC.publisher"CONTENT="O'Reilly &amp; Associates, Inc."><METANAME="DC.date"CONTENT="1998-08-04T21:40:24Z"><METANAME="DC.type"CONTENT="Text.Monograph"><METANAME="DC.format"CONTENT="text/html"SCHEME="MIME"><METANAME="DC.source"CONTENT="1-56592-260-3"SCHEME="ISBN"><METANAME="DC.language"CONTENT="en-US"><METANAME="generator"CONTENT="Jade 1.1/O'Reilly DocBook 3.0 to HTML 4.0"><LINKREV="made"HREF="mailto:online-books@oreilly.com"TITLE="Online Books Comments"><LINKREL="up"HREF="ch22_01.htm"TITLE="22. File Security, Ownership, and Sharing"><LINKREL="prev"HREF="ch22_02.htm"TITLE="22.2 Tutorial on File and Directory Permissions "><LINKREL="next"HREF="ch22_04.htm"TITLE="22.4 Setting an Exact umask "></HEAD><BODYBGCOLOR="#FFFFFF"TEXT="#000000"><DIVCLASS="htmlnav"><H1><IMGSRC="gifs/smbanner.gif"ALT="UNIX Power Tools"USEMAP="#srchmap"BORDER="0"></H1><MAPNAME="srchmap"><AREASHAPE="RECT"COORDS="0,0,466,58"HREF="index.htm"ALT="UNIX Power Tools"><AREASHAPE="RECT"COORDS="467,0,514,18"HREF="jobjects/fsearch.htm"ALT="Search this book"></MAP><TABLEWIDTH="515"BORDER="0"CELLSPACING="0"CELLPADDING="0"><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch22_02.htm"TITLE="22.2 Tutorial on File and Directory Permissions "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 22.2 Tutorial on File and Directory Permissions "BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><B><FONTFACE="ARIEL,HELVETICA,HELV,SANSERIF"SIZE="-1">Chapter 22<BR>File Security, Ownership, and Sharing</FONT></B></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch22_04.htm"TITLE="22.4 Setting an Exact umask "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 22.4 Setting an Exact umask "BORDER="0"></A></TD></TR></TABLE>&nbsp;<HRALIGN="LEFT"WIDTH="515"TITLE="footer"></DIV><DIVCLASS="SECT1"><H2CLASS="sect1"><ACLASS="title"NAME="UPT-ART-0002">22.3 Who Will Own a New File? </A></H2><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-23913"></A><ACLASS="indexterm"NAME="AUTOID-23915"></A>If you share files with other users, it's good to be able to tell whowill own each file.On BSD-based systems, this is even more important because<SPANCLASS="link">only the superuser can change file ownership (<ACLASS="linkend"HREF="ch22_20.htm"TITLE="Why Can't You Change File Ownership Under BSD UNIX?">22.20</A>, <ACLASS="linkend"HREF="ch22_21.htm"TITLE="How to Change File Ownership Without chown">22.21</A>)</SPAN>.</P><OLCLASS="orderedlist"><LICLASS="listitem"><PCLASS="para">When you create a new file, it belongs to you.</P></LI><LICLASS="listitem"><PCLASS="para">When you append to a file with <CODECLASS="literal">&gt;&gt;</CODE><CODECLASS="replaceable"><I>file</I></CODE>, the owner doesn't changebecause UNIX doesn't have to create a new file.</P></LI><LICLASS="listitem"><PCLASS="para">When you rename a file with <EMCLASS="emphasis">mv</EM>, the ownership doesn't change.</P><PCLASS="para">Exception: if you use <EMCLASS="emphasis">mv</EM> to move a file to<SPANCLASS="link">another filesystem (<ACLASS="linkend"HREF="ch01_22.htm"TITLE="How UNIX Keeps Track of Files: Inodes ">1.22</A>)</SPAN>,the moved file will belong to you&nbsp;- because, to move across filesystems,<EMCLASS="emphasis">mv</EM> actually has to copy the file and delete the original.</P></LI><LICLASS="listitem"><PCLASS="para">When you copy a file,<SPANCLASS="link">the copy belongs to you because you created it (<ACLASS="linkend"HREF="ch22_11.htm"TITLE="A Loophole: Modifying Files Without Write Access">22.11</A>)</SPAN>.</P></LI><LICLASS="listitem"><PCLASS="para">When you edit a file:</P><ULCLASS="itemizedlist"><LICLASS="listitem"><PCLASS="para">With an editor like<SPANCLASS="link"><EMCLASS="emphasis">vi</EM> (<ACLASS="linkend"HREF="ch30_02.htm"TITLE="What We Cover ">30.2</A>)</SPAN>,the file keeps its originalowner because a new file is never created.</P></LI><LICLASS="listitem"><PCLASS="para">An editor like<SPANCLASS="link">Emacs (<ACLASS="linkend"HREF="ch32_01.htm#UPT-ART-5540"TITLE="Emacs: The Other Editor ">32.1</A>)</SPAN>,which makes a backup copy, can be different.The backup copy could belong to you or to the original owner.If you replace the edited file with its backup, the file's ownershipmight have changed:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>emacs filea</B></CODE>   ...<EMCLASS="emphasis">Edit a lot, then decide you don't want your changes</EM>...% <CODECLASS="userinput"><B>mv filea~ filea</B></CODE></PRE></BLOCKQUOTE></P></LI></UL></LI></OL><PCLASS="para">If you aren't sure, use<SPANCLASS="link"><EMCLASS="emphasis">ls -l</EM> (<ACLASS="linkend"HREF="ch22_02.htm"TITLE="Tutorial on File and Directory Permissions ">22.2</A>)</SPAN>.</P><DIVCLASS="sect1info"><PCLASS="SECT1INFO">- <SPANCLASS="authorinitials">JP</SPAN></P></DIV></DIV><DIVCLASS="htmlnav"><P></P><HRALIGN="LEFT"WIDTH="515"TITLE="footer"><TABLEWIDTH="515"BORDER="0"CELLSPACING="0"CELLPADDING="0"><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch22_02.htm"TITLE="22.2 Tutorial on File and Directory Permissions "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 22.2 Tutorial on File and Directory Permissions "BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><ACLASS="book"HREF="index.htm"TITLE="UNIX Power Tools"><IMGSRC="gifs/txthome.gif"SRC="gifs/txthome.gif"ALT="UNIX Power Tools"BORDER="0"></A></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch22_04.htm"TITLE="22.4 Setting an Exact umask "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 22.4 Setting an Exact umask "BORDER="0"></A></TD></TR><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172">22.2 Tutorial on File and Directory Permissions </TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><ACLASS="index"HREF="index/idx_0.htm"TITLE="Book Index"><IMGSRC="gifs/index.gif"SRC="gifs/index.gif"ALT="Book Index"BORDER="0"></A></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172">22.4 Setting an Exact umask </TD></TR></TABLE><HRALIGN="LEFT"WIDTH="515"TITLE="footer"><IMGSRC="gifs/smnavbar.gif"SRC="gifs/smnavbar.gif"USEMAP="#map"BORDER="0"ALT="The UNIX CD Bookshelf Navigation"><MAPNAME="map"><AREASHAPE="RECT"COORDS="0,0,73,21"HREF="../index.htm"ALT="The UNIX CD Bookshelf"><AREASHAPE="RECT"COORDS="74,0,163,21"HREF="index.htm"ALT="UNIX Power Tools"><AREASHAPE="RECT"COORDS="164,0,257,21"HREF="../unixnut/index.htm"ALT="UNIX in a Nutshell"><AREASHAPE="RECT"COORDS="258,0,321,21"HREF="../vi/index.htm"ALT="Learning the vi Editor"><AREASHAPE="RECT"COORDS="322,0,378,21"HREF="../sedawk/index.htm"ALT="sed &amp; awk"><AREASHAPE="RECT"COORDS="379,0,438,21"HREF="../ksh/index.htm"ALT="Learning the Korn Shell"><AREASHAPE="RECT"COORDS="439,0,514,21"HREF="../lrnunix/index.htm"ALT="Learning the UNIX Operating System"></MAP></DIV></BODY></HTML>
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