> > >[Chapter 16] 16.5 The Three UNIX File Times > NAME="DC.title" CONTENT="UNIX Power Tools"> NAME="DC.creator" CONTENT="Jerry Peek, Tim O'Reilly & Mike Loukides"> NAME="DC.publisher" CONTENT="O'Reilly & Associates, Inc."> NAME="DC.date" CONTENT="1998-08-04T21:37:38Z"> NAME="DC.type" CONTENT="Text.Monograph"> NAME="DC.format" CONTENT="text/html" SCHEME="MIME"> NAME="DC.source" CONTENT="1-56592-260-3" SCHEME="ISBN"> NAME="DC.language" CONTENT="en-US"> NAME="generator" CONTENT="Jade 1.1/O'Reilly DocBook 3.0 to HTML 4.0"> REV="made" HREF="mailto:online-books@oreilly.com" TITLE="Online Books Comments"> REL="up" HREF="ch16_01.htm" TITLE="16. Where Did I Put That?"> REL="prev" HREF="ch16_04.htm" TITLE="16.4 List All Subdirectories with ls -R "> REL="next" HREF="ch16_06.htm" TITLE='16.6 clf, cls: "Compressed" ls Listings'> > BGCOLOR="#FFFFFF" TEXT="#000000" > CLASS="htmlnav" > > SRC="gifs/smbanner.gif" ALT="UNIX Power Tools" USEMAP="#srchmap" BORDER="0"> > NAME="srchmap" > SHAPE="RECT" COORDS="0,0,466,58" HREF="index.htm" ALT="UNIX Power Tools"> SHAPE="RECT" COORDS="467,0,514,18" HREF="jobjects/fsearch.htm" ALT="Search this book"> > WIDTH="515" BORDER="0" CELLSPACING="0" CELLPADDING="0" > > ALIGN="LEFT" VALIGN="TOP" WIDTH="172" > CLASS="SECT1" HREF="ch16_04.htm" TITLE="16.4 List All Subdirectories with ls -R " > SRC="gifs/txtpreva.gif" SRC="gifs/txtpreva.gif" ALT="Previous: 16.4 List All Subdirectories with ls -R " BORDER="0"> > > ALIGN="CENTER" VALIGN="TOP" WIDTH="171" > > FACE="ARIEL,HELVETICA,HELV,SANSERIF" SIZE="-1" >Chapter 16Where Did I Put That? > > > ALIGN="RIGHT" VALIGN="TOP" WIDTH="172" > CLASS="SECT1" HREF="ch16_06.htm" TITLE='16.6 clf, cls: "Compressed" ls Listings' > SRC="gifs/txtnexta.gif" SRC="gifs/txtnexta.gif" ALT='Next: 16.6 clf, cls: "Compressed" ls Listings' BORDER="0"> > > > > ALIGN="LEFT" WIDTH="515" TITLE="footer"> > CLASS="SECT1" > CLASS="sect1" > CLASS="title" NAME="UPT-ART-0379" >16.5 The Three UNIX File Times > > CLASS="para" >When you're talking to experienced UNIX users, you often hear the terms "change time" and "modification time" thrown around cavalierly. To most people (and most dictionaries), a change and a modification are the same thing. What's the difference here? > CLASS="para" >The difference between a change and a modification is the difference between altering the label on a package and altering its contents. If someone says CLASS="emphasis" >chmod a-w myfile >, that is a change; if someone says CLASS="emphasis" >echo foo >> myfile >, that is a modification. CLASS="indexterm" NAME="AUTOID-16855" > > CLASS="indexterm" NAME="AUTOID-16857" > > A change modifies the file's CLASS="link" >inode ( CLASS="linkend" HREF="ch01_22.htm" TITLE="How UNIX Keeps Track of Files: Inodes " >1.22 >) >; a modification modifies the contents of the file itself. [A file's modification time is also called the CLASS="emphasis" >timestamp >. - CLASS="emphasis" >JP > ] CLASS="indexterm" NAME="AUTOID-16863" > > CLASS="indexterm" NAME="AUTOID-16865" > > CLASS="indexterm" NAME="AUTOID-16868" > > CLASS="indexterm" NAME="AUTOID-16870" > > > CLASS="para" >As long as we're talking about change times and modification CLASS="indexterm" NAME="AUTOID-16875" > > CLASS="indexterm" NAME="AUTOID-16878" > > times, we might as well mention "access times," too. The access time is the last time the file was read or written. So reading a file updates its access time, but not its change time (information about the file wasn't changed) or its modification time (the file itself wasn't changed). > CLASS="para" > CLASS="indexterm" NAME="AUTOID-16882" > >Incidentally, the change time or "ctime" is incorrectly documented as the "creation time" in many places, including some UNIX manuals. Do not believe them. > CLASS="sect1info" > CLASS="SECT1INFO" >- CLASS="authorinitials" >CT > > > > CLASS="htmlnav" > > > ALIGN="LEFT" WIDTH="515" TITLE="footer"> WIDTH="515" BORDER="0" CELLSPACING="0" CELLPADDING="0" > > ALIGN="LEFT" VALIGN="TOP" WIDTH="172" > CLASS="SECT1" HREF="ch16_04.htm" TITLE="16.4 List All Subdirectories with ls -R " > SRC="gifs/txtpreva.gif" SRC="gifs/txtpreva.gif" ALT="Previous: 16.4 List All Subdirectories with ls -R " BORDER="0"> > > ALIGN="CENTER" VALIGN="TOP" WIDTH="171" > CLASS="book" HREF="index.htm" TITLE="UNIX Power Tools" > SRC="gifs/txthome.gif" SRC="gifs/txthome.gif" ALT="UNIX Power Tools" BORDER="0"> > > ALIGN="RIGHT" VALIGN="TOP" WIDTH="172" > CLASS="SECT1" HREF="ch16_06.htm" TITLE='16.6 clf, cls: "Compressed" ls Listings' > SRC="gifs/txtnexta.gif" SRC="gifs/txtnexta.gif" ALT='Next: 16.6 clf, cls: "Compressed" ls Listings' BORDER="0"> > > > > ALIGN="LEFT" VALIGN="TOP" WIDTH="172" >16.4 List All Subdirectories with ls -R > ALIGN="CENTER" VALIGN="TOP" WIDTH="171" > CLASS="index" HREF="index/idx_0.htm" TITLE="Book Index" > SRC="gifs/index.gif" SRC="gifs/index.gif" ALT="Book Index" BORDER="0"> > > ALIGN="RIGHT" VALIGN="TOP" WIDTH="172" >16.6 clf, cls: "Compressed" ls Listings > > > ALIGN="LEFT" WIDTH="515" TITLE="footer"> SRC="gifs/smnavbar.gif" SRC="gifs/smnavbar.gif" USEMAP="#map" BORDER="0" ALT="The UNIX CD Bookshelf Navigation"> NAME="map" > SHAPE="RECT" COORDS="0,0,73,21" HREF="../index.htm" ALT="The UNIX CD Bookshelf"> SHAPE="RECT" COORDS="74,0,163,21" HREF="index.htm" ALT="UNIX Power Tools"> SHAPE="RECT" COORDS="164,0,257,21" HREF="../unixnut/index.htm" ALT="UNIX in a Nutshell"> SHAPE="RECT" COORDS="258,0,321,21" HREF="../vi/index.htm" ALT="Learning the vi Editor"> SHAPE="RECT" COORDS="322,0,378,21" HREF="../sedawk/index.htm" ALT="sed & awk"> SHAPE="RECT" COORDS="379,0,438,21" HREF="../ksh/index.htm" ALT="Learning the Korn Shell"> SHAPE="RECT" COORDS="439,0,514,21" HREF="../lrnunix/index.htm" ALT="Learning the UNIX Operating System"> > > > >
