📄 544-548.html
字号:
<HTML>
<HEAD>
<TITLE>Using Linux:System Maintenance</TITLE>
<META NAME="ROBOTS" CONTENT="NOINDEX, NOFOLLOW">
<SCRIPT>
<!--
function displayWindow(url, width, height) {
var Win = window.open(url,"displayWindow",'width=' + width +
',height=' + height + ',resizable=1,scrollbars=yes');
}
//-->
</SCRIPT>
</HEAD>
-->
<!--ISBN=0789716232//-->
<!--TITLE=Using Linux//-->
<!--AUTHOR=William Ball//-->
<!--PUBLISHER=Macmillan Computer Publishing//-->
<!--IMPRINT=Que//-->
<!--CHAPTER=31//-->
<!--PAGES=544-548//-->
<!--UNASSIGNED1//-->
<!--UNASSIGNED2//-->
<CENTER>
<TABLE BORDER>
<TR>
<TD><A HREF="541-544.html">Previous</A></TD>
<TD><A HREF="../ewtoc.html">Table of Contents</A></TD>
<TD><A HREF="548-550.html">Next</A></TD>
</TR>
</TABLE>
</CENTER>
<P><BR></P>
<P>This command creates (<TT>-c</TT>) an archive file (<TT>f tarfile.tar</TT>) containing all the listed files. The <TT>file(s)</TT> argument can be a directory in a directory tree; <TT>tar</TT> archives everything beneath that directory (inclusive), maintaining all the directory relationships, including links, permissions, ownership information, and date stamps. To tell <TT>tar</TT> exactly what type of archiving job to perform, specify one function as the first argument on the command line (see Table 31.1 for a list of <TT>tar</TT>’s major function identifiers).</P>
<TABLE WIDTH="100%"><CAPTION ALIGN=LEFT><B>TABLE 31.2</B> <I>tar</I>’s major function identifiers
<TR>
<TH COLSPAN="3"><HR>
<TR>
<TH WIDTH="30%" ALIGN="LEFT">Function Identifier
<TH WIDTH="25%" ALIGN="LEFT">Mnenomic
<TH WIDTH="45%" ALIGN="LEFT">Action
<TR>
<TD COLSPAN="3"><HR>
<TR>
<TD VALIGN="TOP"><TT>c</TT>
<TD VALIGN="TOP">create
<TD>Instructs <TT>tar</TT> to make a new archive, putting the listed files and directories in the <TT>tar</TT> file you designate
<TR>
<TD VALIGN="TOP"><TT>x</TT>
<TD VALIGN="TOP">extract
<TD>Instructs <TT>tar</TT> to recreate a set of original files (and directories) using the specified <TT>tar</TT> archive file
<TR>
<TD VALIGN="TOP"><TT>t</TT>
<TD VALIGN="TOP">list
<TD>Generates a list of the listed files that are stored in the <TT>tar</TT> file (if no files are listed on the command line, lists all files in <TT>tar</TT>)
<TR>
<TD VALIGN="TOP"><TT>u</TT>
<TD VALIGN="TOP">update
<TD>Updates an existing <TT>tar</TT> file with the files listed if they are not currently contained in the <TT>tar</TT> file, or have more recent modification times (m times) than the file(s) already contained in the <TT>tar</TT> file
<TR>
<TD VALIGN="TOP"><TT>r</TT>
<TD VALIGN="TOP">append
<TD>Adds listed files to the end of an existing <TT>tar</TT> archive file
<TR>
<TD COLSPAN="3"><HR>
</TABLE>
<P>In addition to using functions to designate the major action it will perform, <TT>tar</TT> accepts dozens of additional options. Listed here are some of the ones most often used:</P>
<TABLE WIDTH="80%"><TR>
<TD WIDTH="35%"><TT>f filename</TT>
<TD WIDTH="65%">Designates <TT>tar</TT> filename
<TR>
<TD VALIGN="TOP"><TT>k</TT>
<TD>Keeps old files (doesn’t overwrite with files being extracted)
<TR>
<TD VALIGN="TOP"><TT>v</TT>
<TD>Verbose (provides information while running)
<TR>
<TD VALIGN="TOP"><TT>z</TT>
<TD>Archives/extracts by using <TT>gzip</TT> compression/decompression
<TR>
<TD VALIGN="TOP"><TT>M</TT>
<TD>Multivolume (indicates an archive that can use several floppy disks or tapes)
<TR>
<TD VALIGN="TOP"><TT>V</TT>
<TD>Volume name (stored in <TT>tar</TT> file for reference)
</TABLE>
<P><FONT SIZE="+1"><B>Using <I>tar</I> to Archive Directories
</B></FONT></P>
<P><TT>tar</TT> can archive an entire directory if you use a directory name on the command line:</P>
<!-- CODE //-->
<PRE>
#pwd
/public/sharedfiles/me
#ls -l
total 27
—rwxrwxr—x 1 me users 22843 Apr 1 20:40
README.txt
—rwxrwxr—x 1 me me 1519 Mar 15 21:29
iousage
drwxrwxr—x 2 me users 1024 Jun 8 1996
fileshare
lrwxrwxr—x 2 me users 8 Dec 12 20:39
thtfil -> thisfile
# tar cf share.tar /public/sharedfiles/me
tar: removing leading / from absolute pathnames in the archive
#ls -l
total 28
—rwxrwxr—x 1 me users 22843 Apr 1 20:40
README.txt
—rwxrwxr—x 1 me me 1519 Mar 15 21:29
iousage
drwxrwxr—x 2 me users 1024 Jun 8 1996
fileshare
—rwxrwxr—x 1 me users 46058 Apr 1 20:40
share.tar
lrwxrwxr—x 2 me users 8 Dec 12 20:39
thtfil -> thisfile
</PRE>
<!-- END CODE //-->
<P><TT>tar</TT> uses relative pathnames; it creates an archive of the <TT>me</TT> directory in the preceding code without referring to the root pathname (the first slash). (That’s what the <TT>tar: ...</TT> system message means.) You can place archived directories in other directories without worrying about the archive’s original pathnames and parent directories.</P>
<P>You can think of <TT>tar</TT> as a way to graft a directory branch to another directory tree; you can use one <TT>tar</TT> file to move an entire set of directories and subdirectories from place to place on your system, or from system to system (many ftp files are <TT>tar</TT> files).</P>
<P><FONT SIZE="+1"><B>Moving and Extracting <I>tar</I> Files
</B></FONT></P>
<P>After you create a <TT>tar</TT> file, anyone with read and write permissions for the directory containing the file (such as the user <TT>notme</TT>) needs to add the <TT>me</TT> directory that was archived earlier to his or her home directory:</P>
<!-- CODE //-->
<PRE>
#pwd
/home/notme
#ls -l
total 53
—rw—rw—r– 1 notme users 8432 Apr 1 20:40
zipcode.c
—rw—rw—r– 1 notme users 21519 Mar 14 21:29
stadd.o
drwxrwxr—x 2 notme users 1024 Dec 4 20:39
docfiles
drwxr-xr– 1 notme users 1024 Jan 11 1996
perlscripts
drw—r---r– 2 notme users 1024 Mar 14 21:29
progfiles
#cp /public/sharedfiles/me/share.tar .
#tar xvf share.tar
public/sharedfiles/me/README.txt
public/sharedfiles/me/iousage
...
#ls -l
total 80
—rw—rw—r---- 1 notme users 8432 Apr 1 20:40
zipcode.c
—rw—rw—r---- 1 notme users 21519 Mar 14 21:29
stadd.o
drwxrwxr—x 2 notme users 1024 Dec 4 20:39
docfiles
drwxr-xr---- 1 notme users 1024 Jan 11 1996
perlscripts
drw—r---r---- 2 notme users 1024 Mar 14 21:29
progfiles
drwxrwxrwx 2 notme users 1024 Apr 1 1996 public
#ls -l public
drwxrwxr-x 2 notme users 1024 Aug 17 08:42 me
</PRE>
<!-- END CODE //-->
<P>Because the user <TT>notme</TT> ran the <TT>tar</TT> extraction command, the extracted directory <TT>public</TT> (and its subdirectories) are now owned by <TT>notme</TT> rather than <TT>me</TT>. The <TT>v</TT> (verbose) option in the last example provides a listing of relative pathnames for each file <TT>tar</TT> processes (abbreviated for space). Increasing the number of <TT>v</TT> options listed increases the amount of information <TT>tar</TT> provides (<TT>vv</TT> lists date stamps and sizes as well as pathnames, like the <TT>ls -l</TT> command).</P><P><BR></P>
<CENTER>
<TABLE BORDER>
<TR>
<TD><A HREF="541-544.html">Previous</A></TD>
<TD><A HREF="../ewtoc.html">Table of Contents</A></TD>
<TD><A HREF="548-550.html">Next</A></TD>
</TR>
</TABLE>
</CENTER>
</td>
</tr>
</table>
<!-- begin footer information -->
</body></html>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -