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diff --git a/misc/slackbook/html/archive-files-tar.html b/misc/slackbook/html/archive-files-tar.html new file mode 100644 index 00000000..b23db4b1 --- /dev/null +++ b/misc/slackbook/html/archive-files-tar.html @@ -0,0 +1,232 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" + "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml"> +<head> +<meta name="generator" content="HTML Tidy, see www.w3.org" /> +<title>tar</title> +<meta name="GENERATOR" content="Modular DocBook HTML Stylesheet Version 1.7" /> +<link rel="HOME" title="Slackware Linux Essentials" href="index.html" /> +<link rel="UP" title="Archive Files" href="archive-files.html" /> +<link rel="PREVIOUS" title="bzip2" href="archive-files-bzip2.html" /> +<link rel="NEXT" title="zip" href="archive-files-zip.html" /> +<link rel="STYLESHEET" type="text/css" href="docbook.css" /> +<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> +</head> +<body class="SECT1" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#840084" +alink="#0000FF"> +<div class="NAVHEADER"> +<table summary="Header navigation table" width="100%" border="0" cellpadding="0" +cellspacing="0"> +<tr> +<th colspan="3" align="center">Slackware Linux Essentials</th> +</tr> + +<tr> +<td width="10%" align="left" valign="bottom"><a href="archive-files-bzip2.html" +accesskey="P">Prev</a></td> +<td width="80%" align="center" valign="bottom">Chapter 15 Archive Files</td> +<td width="10%" align="right" valign="bottom"><a href="archive-files-zip.html" +accesskey="N">Next</a></td> +</tr> +</table> + +<hr align="LEFT" width="100%" /> +</div> + +<div class="SECT1"> +<h1 class="SECT1"><a id="ARCHIVE-FILES-TAR" name="ARCHIVE-FILES-TAR">15.3 <tt +class="COMMAND">tar</tt></a></h1> + +<p><tt class="COMMAND">tar</tt>(1) is the GNU tape archiver. It takes several files or +directories and creates one large file. This allows you to compress an entire directory +tree, which is impossible by just using <tt class="COMMAND">gzip</tt> or <tt +class="COMMAND">bzip2</tt>. <tt class="COMMAND">tar</tt> has many command line options, +which are explained in its man page. This section will just cover the most common uses of +<tt class="COMMAND">tar</tt>.</p> + +<p>The most common use for <tt class="COMMAND">tar</tt> is to decompress and unarchive a +package that you've downloaded from a web site or ftp site. Most files will come with a +<tt class="FILENAME">.tar.gz</tt> extension. This is commonly known as a +“tarball”. It means that several files were archived using <tt +class="COMMAND">tar</tt> and then compressed using <tt class="COMMAND">gzip</tt>. You +might also see this listed as a <tt class="FILENAME">.tar.Z</tt> file. It means the same +thing, but this is usually encountered on older Unix systems.</p> + +<p>Alternatively, you might find a <tt class="FILENAME">.tar.bz2</tt> file somewhere. +Kernel source is distributed as such because it is a smaller download. As you might have +guessed, this is several files archived with <tt class="COMMAND">tar</tt> and then +bzipped.</p> + +<p>You can get to all the files in this archive by making use of <tt +class="COMMAND">tar</tt> and some command line arguments. Unarchiving a tarball makes use +of the <var class="OPTION">-z</var> flag, which means to first run the file through <tt +class="COMMAND">gunzip</tt> and decompress it. The most common way to decompress a +tarball is like so:</p> + +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="SCREEN"> +<samp class="PROMPT">%</samp> <kbd class="USERINPUT">tar -xvzf filename.tar.gz</kbd> +</pre> +</td> +</tr> +</table> + +<p>That's quite a few options. So what do they all mean? The <var class="OPTION">-x</var> +means to extract. This is important, as it tells <tt class="COMMAND">tar</tt> exactly +what to do with the input file. In this case, we'll be splitting it back up into all the +files that it came from. <var class="OPTION">-v</var> means to be verbose. This will list +all the files that are being unarchived. It is perfectly acceptable to leave this option +off, if somewhat boring. Alternatively, you could use <var class="OPTION">-vv</var> to be +very verbose and list even more information about each file being unarchived. The <var +class="OPTION">-z</var> option tells <tt class="COMMAND">tar</tt> to run <tt +class="FILENAME">filename.tar.gz</tt> through <tt class="COMMAND">gunzip</tt> first. And +finally, the <var class="OPTION">-f</var> option tells <tt class="COMMAND">tar</tt> that +the next string on the command line is the file to operate on.</p> + +<p>There are a few other ways to write this same command. On older systems lacking a +decent copy of GNU <tt class="COMMAND">tar</tt>, you might see it written like so:</p> + +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="SCREEN"> +<samp class="PROMPT">%</samp> <kbd +class="USERINPUT">gunzip filename.tar.gz | tar -xvf -</kbd> +</pre> +</td> +</tr> +</table> + +<p>This command line will uncompress the file and send the output to <tt +class="COMMAND">tar</tt>. Since <tt class="COMMAND">gzip</tt> will write its output to +standard out if told to do so, this command will write the decompressed file to standard +out. The pipe then sends it to <tt class="COMMAND">tar</tt> for unarchiving. The +“-” means to operate on standard input. It will unarchive the stream of data +that it gets from <tt class="COMMAND">gzip</tt> and write that to the disk.</p> + +<p>Another way to write the first command line is to leave off the dash before the +options, like so:</p> + +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="SCREEN"> +<samp class="PROMPT">%</samp> <kbd class="USERINPUT">tar xvzf filename.tar.gz</kbd> +</pre> +</td> +</tr> +</table> + +<p>You might also encounter a bzipped archive. The version of <tt +class="COMMAND">tar</tt> that comes with Slackware Linux can handle these the same as +gzipped archives. Instead of the <var class="OPTION">-z</var> command line option, you'd +use <var class="OPTION">-j</var>:</p> + +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="SCREEN"> +<samp class="PROMPT">%</samp> <kbd class="USERINPUT">tar -xvjf filename.tar.bz2</kbd> +</pre> +</td> +</tr> +</table> + +<p>It is important to note that <tt class="COMMAND">tar</tt> will place the unarchived +files in the current directory. So, if you had an archive in <tt +class="FILENAME">/tmp</tt> that you wanted to decompress into your home directory, there +are a few options. First, the archive could be moved into your home directory and then +run through <tt class="COMMAND">tar</tt>. Second, you could specify the path to the +archive file on the command line. Third, you can use the <var class="OPTION">-C</var> +option to “explode” the tarball in a specified directory.</p> + +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="SCREEN"> +<samp class="PROMPT">%</samp> <kbd class="USERINPUT">cd $HOME</kbd> +<samp class="PROMPT">%</samp> <kbd class="USERINPUT">cp /tmp/filename.tar.gz .</kbd> +<samp class="PROMPT">%</samp> <kbd class="USERINPUT">tar -xvzf filename.tar.gz</kbd> + +<samp class="PROMPT">%</samp> <kbd class="USERINPUT">cd $HOME</kbd> +<samp class="PROMPT">%</samp> <kbd class="USERINPUT">tar -xvzf /tmp/filename.tar.gz</kbd> + +<samp class="PROMPT">%</samp> <kbd class="USERINPUT">cd /</kbd> +<samp class="PROMPT">%</samp> <kbd +class="USERINPUT">tar -xvzf /tmp/filename.tar.gz -C $HOME</kbd> +</pre> +</td> +</tr> +</table> + +<p>All the above statements are equivalent. In each case, the archive is unpacked inside +your home directory and the original uncompressed archive is left in place.</p> + +<p>So what good is being able to uncompress these archives if you can't make them? Well, +<tt class="COMMAND">tar</tt> handles that too. In most cases it's as easy as removing the +“<var class="OPTION">-x</var>” option and replacing it with the “<var +class="OPTION">-c</var>” option.</p> + +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="SCREEN"> +<samp class="PROMPT">%</samp> <kbd class="USERINPUT">tar -cvzf filename.tar.gz .</kbd> +</pre> +</td> +</tr> +</table> + +<p>In this command line, the <var class="OPTION">-c</var> option tells <tt +class="COMMAND">tar</tt> to create an archive, while the <var class="OPTION">-z</var> +option runs the resulting archive file through <tt class="COMMAND">gzip</tt> to compress +it. <tt class="FILENAME">filename.tar.gz</tt> is the file that you want to create.</p> + +<p>Specifying the “<var class="OPTION">-f</var>” option isn't always +necessary, but is typically good practice anyway. Without it, <tt +class="COMMAND">tar</tt> writes to standard output, which is usually desired for piping +<tt class="COMMAND">tar</tt>'s output to another program, like so.</p> + +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="SCREEN"> +<samp class="PROMPT">%</samp> <kbd +class="USERINPUT">tar -cv filename.tar . | gpg --encrypt</kbd> +</pre> +</td> +</tr> +</table> + +<p>That command creates an non-compressed tar archive of the current directory, pipes the +tarball through <tt class="COMMAND">gpg</tt> which encrypts and compresses the tarball, +making it realistically impossible to read by anyone other than the person knowing the +secret key.</p> +</div> + +<div class="NAVFOOTER"> +<hr align="LEFT" width="100%" /> +<table summary="Footer navigation table" width="100%" border="0" cellpadding="0" +cellspacing="0"> +<tr> +<td width="33%" align="left" valign="top"><a href="archive-files-bzip2.html" +accesskey="P">Prev</a></td> +<td width="34%" align="center" valign="top"><a href="index.html" +accesskey="H">Home</a></td> +<td width="33%" align="right" valign="top"><a href="archive-files-zip.html" +accesskey="N">Next</a></td> +</tr> + +<tr> +<td width="33%" align="left" valign="top"><tt class="COMMAND">bzip2</tt></td> +<td width="34%" align="center" valign="top"><a href="archive-files.html" +accesskey="U">Up</a></td> +<td width="33%" align="right" valign="top"><tt class="COMMAND">zip</tt></td> +</tr> +</table> +</div> +</body> +</html> + |