linux-partition.html

Linus guide, Linus guide, Linus guide,

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			<P><TT><B>/lib</B></TT></P>
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			<P ALIGN=LEFT><FONT SIZE=4>HINT:&nbsp;&nbsp;&nbsp;&nbsp;<B>Don't
			ever delete stuff in here or change permissions unless you really
			know what you're doing.</B></FONT></P>
			<P ALIGN=LEFT><FONT SIZE=4>Files in the /lib directory are
			&quot;chunks&quot; of programs that are shared and needed by other
			programs in order to run.</FONT></P>
			<P ALIGN=LEFT><FONT SIZE=4>This is a LIBRARY of functions that
			programs can use.</FONT></P>
			<P ALIGN=LEFT><FONT SIZE=4>Many of the library files in this
			directory wrapper the actual interface to the operating system
			that all the programs on the system use... say, to Open a File.
			<BR><BR><A HREF="file:/lib">Click
			here to see your own /lib directory</A></FONT></P>
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			<P><TT><B>/etc</B></TT></P>
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			<P ALIGN=LEFT><FONT SIZE=4>Configuration files, scripts, etc., -
			pardon the pun, go under this directory.</FONT></P>
			<P ALIGN=LEFT><FONT SIZE=4>Relative to partitions, you'll want to
			peek at fstab, mtab... Heck, check out *tab, anything ending in
			tab.</FONT></P>
			<P ALIGN=LEFT><FONT SIZE=4>Often, *tab files have man pages, so
			you can type &quot;man &lt;something&gt;tab&quot; and read about
			what that file is doing here.</FONT></P>
			<P ALIGN=LEFT><FONT SIZE=4>Another excellent thing to know is that
			the system's knowledge of users and passwords is stored in the
			/etc directory in a file called passwd.</FONT></P>
			<P ALIGN=LEFT><FONT SIZE=4>Take a peek at that, definitely, also
			the file called group or groups.</FONT></P>
			<P ALIGN=LEFT><FONT SIZE=4>Also, anything relative to configuring
			networking, the scripts that run when you startup and shutdown
			your system, and so on, all the good config files go in /etc.</FONT></P>
			<P ALIGN=LEFT><FONT SIZE=4>Look in the rc.d directory under
			/etc.&nbsp;&nbsp;&nbsp;&nbsp;There, you'll find all the startup
			scripts your system runs when it is booting up, configuring
			networking, mounting partitions, etc.,</FONT></P>
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				<LI><P ALIGN=LEFT><FONT SIZE=4><A HREF="file:/etc">Click
				here to see your own /etc directory</A> </FONT>
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				<LI><P ALIGN=LEFT><FONT SIZE=4><A HREF="file:/etc/passwd">Click
				here to TRY and see your passwd file</A> </FONT>
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				<LI><P ALIGN=LEFT><FONT SIZE=4><A HREF="file:/etc/fstab">Click
				here to see your fstab file</A> </FONT>
				</P>
				<LI><P ALIGN=LEFT><FONT SIZE=4><A HREF="file:/etc/mtab">Click
				here to see your mtab file</A> </FONT>
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				<LI><P ALIGN=LEFT><FONT SIZE=4><A HREF="file:/etc/rc.d">Click
				here to see your /etc/rc.d directory</A> </FONT>
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			<P><TT><B>/dev</B></TT></P>
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			<P ALIGN=LEFT><FONT SIZE=4>This is my favorite directory. </FONT>
			</P>
			<P ALIGN=LEFT><FONT SIZE=4>It is perhaps best to say that /dev is
			a directory but the files in it are not really files...&nbsp;&nbsp;&nbsp;&nbsp;Anyway,
			these are your DEVICES, printer, scanner, serial ports, modems,
			hard disk drives ! </FONT>
			</P>
			<P ALIGN=LEFT><FONT SIZE=4>Your hard disk drive is probably known
			as &quot;/dev/hda&quot; and your partitions are known as
			&quot;/dev/hda1&quot; &quot;/dev/hda2&quot; etc., That's for IDE
			drives. </FONT>
			</P>
			<P ALIGN=LEFT><FONT SIZE=4>SCSI drives are known as &quot;/dev/sda&quot;,
			like that. </FONT>
			</P>
			<P ALIGN=LEFT><FONT SIZE=4>Somewhere there's a doc that talks
			about all the files in /dev... </FONT>
			</P>
			<P ALIGN=LEFT><FONT SIZE=4>Here is a couple of examples that are
			insightful as to how Linux itself uses this directory... </FONT>
			</P>
			<P ALIGN=LEFT><FONT SIZE=4>You can copy a file to /dev/lp0 and it
			will print instead of making a file /dev/lp0. </FONT>
			</P>
			<P ALIGN=LEFT><FONT SIZE=4>You can &quot;setserial /dev/ttyS2 irq
			5&quot; and this will set your COM3 to IRQ 5... </FONT>
			</P>
			<P ALIGN=LEFT><FONT SIZE=4>You can &quot;mknod&quot; to create a
			device file in this directory if it doesn't already exist by
			default. This assumes the Kernel knows what the device is even if
			there isn't already a stub for it in this directory... </FONT>
			</P>
			<P ALIGN=LEFT><FONT SIZE=4>When you rebuild the Linux kernel you
			will enable and disable various types of devices, this may require
			you to use <B>mknod</B><SPAN STYLE="font-weight: medium"> before
			the devices actually work.</SPAN></FONT></P>
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			<P><TT><B>/root</B></TT></P>
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			<P ALIGN=LEFT><FONT SIZE=4>When you create a user in Linux usually
			their HOME DIRECTORY is created under /home. This directory is the
			HOME directory of the <TT><B>root</B></TT> user, the user than can
			do anything.</FONT></P>
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			<P><TT><B>/usr</B></TT></P>
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			<P ALIGN=LEFT><FONT SIZE=4>Under this directory go things, files,
			programs, that are either created by users for use by other users,
			or for things useful to users. </FONT>
			</P>
			<P ALIGN=LEFT><FONT SIZE=4>When you see <B>RTFM</B> in an email
			message, it means that you should go to <B>/usr/doc</B> and <B>READ
			THE FREAKING MANUAL</B>, which is to be found here in the form of
			lots of little documents, subdirectories, HTML files, etc., </FONT>
			</P>
			<P ALIGN=LEFT><FONT SIZE=4>ALSO, if you feel ready for it and want
			to rebuild your Linux kernel, the source code you will need to
			compile is almost always to be found under
			/usr/src/linux.&nbsp;&nbsp;&nbsp;&nbsp;Change directories with cd
			to /usr/src and then do &quot;ls -al linux&quot;.</FONT></P>
			<P ALIGN=LEFT><FONT SIZE=4>You will see usually that this is a
			symbolic link to some big huge long directory name that indicates
			the kernel source version. If you don't see any of this stuff it
			means you have not installed the kernel source and you will not be
			able to play with it until you do.</FONT></P>
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				<LI><P ALIGN=LEFT><FONT SIZE=4><A HREF="file:/usr">Click
				here to see your own /usr directory</A> </FONT>
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				<LI><P ALIGN=LEFT><FONT SIZE=4><A HREF="file:/usr/doc">Click
				here to see /usr/doc directory</A> </FONT>
				</P>
				<LI><P ALIGN=LEFT><FONT SIZE=4><A HREF="file:/usr/src/linux">Click
				here to TRY and see your Linux Kernel Source tree</A> </FONT>
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			<P><TT><B>/home</B></TT></P>
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			<P ALIGN=LEFT><FONT SIZE=4>Here is the first good example
			candidate for a partition !</FONT></P>
			<P ALIGN=LEFT><FONT SIZE=4>User's home directories...&nbsp;&nbsp;&nbsp;&nbsp;Who
			knows how much crap users are going to create. </FONT>
			</P>
			<P ALIGN=LEFT><FONT SIZE=4>If all you have is one big partition
			for everything and it fills up, your system will crash. </FONT>
			</P>
			<P ALIGN=LEFT><FONT SIZE=4>If the part of your directory tree that
			fills up is itself a partition, then that part of your directory
			tree fills up and crashes and not your whole machine.</FONT></P>
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			<P><TT><B>/boot</B></TT></P>
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			<P ALIGN=LEFT><FONT SIZE=4>After you build a kernel, it's image is
			placed here. </FONT>
			</P>
			<P ALIGN=LEFT><FONT SIZE=4>Also, when you install Linux a backup
			copy of the original boot record goes here, say, if you had first
			installed Windows 98.</FONT></P>
			<P ALIGN=LEFT><FONT SIZE=4>You can put it back the original Master
			Boot Record with the <B>lilo</B> command. - see &quot;man lilo&quot;
			for details...&nbsp;&nbsp;&nbsp;&nbsp;If you want your Windows to
			come back to life, for example, after having seemingly ruined it.</FONT></P>
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			<P><TT><B>/mnt</B></TT></P>
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			<P ALIGN=LEFT><FONT SIZE=4>That looks like short for MOUNT !</FONT></P>
			<P ALIGN=LEFT><FONT SIZE=4>What do you bet there are
			subdirectories under /mnt that are completely empty ? </FONT>
			</P>
			<P ALIGN=LEFT><FONT SIZE=4>These are complimentary default Mount
			Points for things like your floppy disk, CD ROM drive, etc., </FONT>
			</P>
			<P ALIGN=LEFT><FONT SIZE=4>An example of how this works:&nbsp;&nbsp;&nbsp;&nbsp;Go
			to the /mnt directory, &quot;cd /mnt&quot;, then type &quot;ls&quot;.
			</FONT>
			</P>
			<P ALIGN=LEFT><FONT SIZE=4>Put in a CD ROM, then type &quot;mount
			cdrom&quot;.</FONT></P>
			<P ALIGN=LEFT><FONT SIZE=4>You can now &quot;cd /mnt/cdrom&quot;
			and use &quot;ls&quot; to see the contents of your CD ROM. </FONT>
			</P>
			<P ALIGN=LEFT><FONT SIZE=4>If you then type cd /mnt, and umount
			cdrom you will note that the directory /mnt/cdorm is now
			empty.<BR><BR><A HREF="file:/mnt">Click
			here to see your own /mnt directory</A></FONT></P>
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			<P><TT><B>/opt</B></TT></P>
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			<P ALIGN=LEFT><FONT SIZE=4>The recent trend in standardizing Unix
			directory tree structures suggests that third party applications
			go in /opt, things like Apache, Netscape Server, Oracle, etc., </FONT>
			</P>
			<P ALIGN=LEFT><FONT SIZE=4>Although on Redhat, you'll likely find
			Apache located under &quot;/etc/httpd&quot;</FONT></P>
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			<P><TT><B>/proc</B></TT></P>
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			<P ALIGN=LEFT><FONT SIZE=4>This is truly a directory that's not a
			directory. </FONT>
			</P>
			<P ALIGN=LEFT><FONT SIZE=4>This is a pseudo file system. </FONT>
			</P>
			<P ALIGN=LEFT><FONT SIZE=4>All files you find here are stubs for
			accessing the kernel's data as it runs. </FONT>
			</P>
			<P ALIGN=LEFT><FONT SIZE=4>If you view the contents of a file in
			here you'll see live data come out of the kernel, and not the
			static contents of a file. </FONT>
			</P>
			<P ALIGN=LEFT><FONT SIZE=4>Don't play with /proc, don't make a
			partition for it... Unless you're a guru, just ignore this.</FONT></P>
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			<P><TT><B>/var</B></TT></P>
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			<P ALIGN=LEFT><FONT SIZE=4>Variable Stuff goes in /var, log files,
			MAIL MESSAGES, your Email Inbox, temporary holdings of incoming
			and outgoing mail... </FONT>
			</P>
			<P ALIGN=LEFT><FONT SIZE=4>This part of the directory tree usually
			ends up growing and growing... and will eventually fill up if you