164-166.html
来自「linux-unix130.linux.and.unix.ebooks130 l」· HTML 代码 · 共 140 行
HTML
140 行
<HTML>
<HEAD>
<TITLE>Linux Unleashed, Third Edition:Using the File System</TITLE>
<SCRIPT>
<!--
function displayWindow(url, width, height) {
var Win = window.open(url,"displayWindow",'width=' + width +
',height=' + height + ',resizable=1,scrollbars=yes');
}
//-->
</SCRIPT>
</HEAD>
-->
<!--ISBN=0672313723//-->
<!--TITLE=Linux Unleashed, Third Edition//-->
<!--AUTHOR=Tim Parker//-->
<!--PUBLISHER=Macmillan Computer Publishing//-->
<!--IMPRINT=Sams//-->
<!--CHAPTER=8//-->
<!--PAGES=164-166//-->
<!--UNASSIGNED1//-->
<!--UNASSIGNED2//-->
<CENTER>
<TABLE BORDER>
<TR>
<TD><A HREF="161-164.html">Previous</A></TD>
<TD><A HREF="../ewtoc.html">Table of Contents</A></TD>
<TD><A HREF="167-170.html">Next</A></TD>
</TR>
</TABLE>
</CENTER>
<P><BR></P>
<P>When you use <TT><B>cp</B></TT>, you are actually making a second physical copy of your file and placing it on your disk. This can be slower (although for small files, you won’t notice any difference), and it causes a bit more wear and tear on your computer. Don’t make copies of files when all you really want to do is move them!</P>
<H4 ALIGN="LEFT"><A NAME="Heading19"></A><FONT COLOR="#000077">Moving and Copying with Wildcards</FONT></H4>
<P>If you have 20 files in a directory, and you want to copy them to another directory, it would be very tedious to use the <TT><B>cp</B></TT> command on each one. Fortunately, you can use the wildcards <B>*</B> and <B>?</B> to copy more than one file at a time.</P>
<P>If you want to move or copy <I>all</I> files in a directory, use the wildcard <B>*</B>:</P>
<!-- CODE SNIP //-->
<PRE>
darkstar:~$ <B>cp * /tmp</B>
</PRE>
<!-- END CODE SNIP //-->
<P>This command copies every file in your current directory to the directory <TT><B>/tmp</B></TT>.</P>
<P>You can use <B>*</B> along with other characters to match only certain files. For instance, suppose you have a directory that contains the files <TT><B>book1</B></TT>, <TT><B>book_idea</B></TT>, <B>book-chapter-1</B>, and <TT><B>poem.book</B></TT>. To copy just the first three files, you can type <TT><B>cp book* /tmp</B></TT>. When you type <TT><B>book*</B></TT>, you are asking Linux to match all files whose names start with <TT><B>book</B></TT>. In this case, <TT><B>poem.book</B></TT> does not start with <TT><B>book</B></TT>, so there is no way <TT><B>book*</B></TT> can match it. (Note that if your filename were <TT><B>book.poem, book*</B></TT> would match it.)</P>
<P>As you saw at the outset, <TT><B>mv</B></TT> and <TT><B>cp</B></TT> are very simple commands. It’s specifying the files that is the complicated part! If things still seem confusing, don’t worry. Even experts sometimes mess up “simple” moves and copies. Follow the examples and try any different ways you can think of. There is a definite logic as to how the files to be moved and copied should be specified. It takes a while to become familiar with this logic, and you will probably have to practice a while before these things become intuitive.</P>
<H4 ALIGN="LEFT"><A NAME="Heading20"></A><FONT COLOR="#000077">Moving Directories</FONT></H4>
<P>To move a directory, use the <TT><B>mv</B></TT> command. The syntax is <TT><B>mv</B> <<I>directory</I>> <<I>destination</I>></TT>. In the following example, let’s move the <TT><B>newdir</B></TT> subdirectory found in your current directory to the <TT><B>/tmp</B></TT> directory:</P>
<!-- CODE SNIP //-->
<PRE>
darkstar:~$ <B>mvdir newdir /tmp</B>
darkstar:~$ <B>cd /tmp</B>
darkstar:/tmp$ <B>ls</B>
/newdir
</PRE>
<!-- END CODE SNIP //-->
<P>The directory <TT><B>newdir</B></TT> is now a subdirectory of <TT><B>/tmp</B></TT>.</P>
<P>When you move a directory, all its files and subdirectories go with it.</P>
<P>You can use the <TT><B>mv</B></TT> command to rename a directory without moving it. For example, if you want to rename the directory <TT><B>newdir</B></TT> to <TT><B>olddir</B></TT> without copying it, the command</P>
<!-- CODE SNIP //-->
<PRE>
mv newdir olddir
</PRE>
<!-- END CODE SNIP //-->
<P>does the task. All the files in <TT><B>newdir</B></TT> now are under <TT><B>olddir</B></TT>.</P>
<H3><A NAME="Heading21"></A><FONT COLOR="#000077">Removing Files and Directories</FONT></H3>
<P>Now that you know how to create files and directories, it’s time to learn how to undo your handiwork.
</P>
<P>To remove (or delete) a file, use the <TT><B>rm</B></TT> command (<TT><B>rm</B></TT> is a very terse spelling of <I>remove</I>). The syntax is <TT><B>rm</B> <<I>filename</I>></TT>. For example, the command:</P>
<!-- CODE SNIP //-->
<PRE>
darkstar:~$ <B>rm dead_duck</B>
</PRE>
<!-- END CODE SNIP //-->
<P>removes the file <TT><B>dead_duck</B></TT> from your current directory.</P>
<!-- CODE SNIP //-->
<PRE>
darkstar:~$ <B>rm /tmp/dead_duck</B>
</PRE>
<!-- END CODE SNIP //-->
<P>removes the file <TT><B>dead_duck</B></TT> from the <TT><B>/tmp</B></TT> directory.</P>
<P>You can use wildcards with the <TT><B>rm</B></TT> command, just as with all other Linux commands. This can cause you a lot of problems when you type the command at the wrong location. For example, the command</P>
<!-- CODE SNIP //-->
<PRE>
darkstar:~$ <B>rm *</B>
</PRE>
<!-- END CODE SNIP //-->
<P>removes all files from your current directory. There’s no way to undelete the files, so if you issued this command by accident, you’re out of luck. The moral of the story is to be very careful when using wildcards with the <TT><B>rm</B></TT> command!</P>
<P>You can combine wildcards and directory paths. For example, the command</P>
<!-- CODE SNIP //-->
<PRE>
darkstar:~$ <B>rm /tmp/*duck</B>
</PRE>
<!-- END CODE SNIP //-->
<P>removes all files ending in <TT><B>duck</B></TT> from the <TT><B>/tmp</B></TT> directory.</P>
<P>As soon as a file is removed, it is <I>gone!</I> Always think about what you’re doing before you remove a file. You can use one of the following options to keep out of trouble when using wildcards:</P>
<DL>
<DD><B>•</B> Run <TT><B>ls</B></TT> using the same file specification you use with the <TT><B>rm</B></TT> command. For instance:
<!-- CODE SNIP //-->
<PRE>
darkstar:~$ <B>ls *duck
</B>dead_duck guiduck lame-duck
:~$ rm *duck
</PRE>
<!-- END CODE SNIP //-->
<BR>In this case, you <I>thought</I> you wanted to remove all files that matched <TT><B>*duck</B></TT>. To verify that this indeed was the case, all the <TT><B>*duck</B></TT> files were listed (wildcards work the same way with all commands). The listing looked okay, so you went ahead and removed the files.
<DD><B>•</B> Use the <TT><B>i</B></TT> (interactive) option with <TT><B>rm</B></TT>:
<!-- CODE SNIP //-->
<PRE>
darkstar:~$ rm -i *duck
rm: remove ‘dead_duck’? y
rm: remove ‘guiduck’? n
rm: remove ‘lame-duck’? y
darkstar:~$
</PRE>
<!-- END CODE SNIP //-->
<BR>When you use <TT><B>rm -i</B></TT>, the command goes through the list of files to be deleted one by one, prompting you for the okay to remove the file. If you type <TT><B>y</B></TT> or <TT><B>Y</B></TT>, <TT><B>rm</B></TT> removes the file. If you type any other character, <TT><B>rm</B></TT> does not remove it. The only disadvantage of using this interactive mode is that it can be very tedious when the list of files to be removed is long.
</DL>
<P><BR></P>
<CENTER>
<TABLE BORDER>
<TR>
<TD><A HREF="161-164.html">Previous</A></TD>
<TD><A HREF="../ewtoc.html">Table of Contents</A></TD>
<TD><A HREF="167-170.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
增大字号Ctrl + =
减小字号Ctrl + -
显示快捷键?