linux-commands.html

Linus guide, Linus guide, Linus guide,

remove it with <B><TT>rm -rf</TT></B> later on.
If you have only a single partition that makes up your filesystem then you
have very little to worry about in this area.</P>

<A NAME="rm"></A>
<H4><A NAME="10">rm</A></H4>

<P>The <B>rm</B> command is used for <B>r</B>e<B>m</B>oving files. You use
it just like the <B>del</B> or <B>delete</B> command in MS-DOS. Let's say
you want to remove a file called <TT>foobar</TT> in your current
directory. To do that, simply type <B><TT>rm foobar</TT></B>. Note that
there is no &quot;Recycle Bin&quot; like in Windows 95. So when you delete
a file, it's gone for good.</P>

<P>To delete something in some other directory, use the full path as the
file name. For example, if you want to delete a file called
&quot;windows&quot; that's in the directory /usr/local/src/, you would
type <B><TT>rm /usr/local/src/windows</TT></B>.</P>

<P>To remove an entire directory and its contents, type <B><TT>rm -rf
/directory</TT></B> where &quot;/directory&quot; is the path to the
directory that you want to delete. If you're wondering, the &quot;rf&quot;
stands for &quot;recursive&quot; and &quot;force&quot;. Be very careful
with this command, as it can wreak havoc easily if misused.</P>

<!-- Editing section started on June 9, 1999 -->
<!-- Last updated ~ Wed Jun  9 22:07:27 PDT 1999 -->

<A NAME="Editing"></A>
<H3><A NAME="11">Editing</A></H3>

<P>If you haven't figured out how important a text editor is, you soon
will. Graphical interfaces can't shield you forever, and those utilities
have their limits. Besides, if you're reading this page, I'm inclined to
think that you want to be able to customize beyond the capabilities of
graphical utilities. You want to work at the command prompt. I know you
do.</P>

<P>The basic syntax to invoke these text editors is the same. Type the
name of the editor followed by the file you want to edit, separated by a
space in between. Non-existent files will be blank. Blank files will be
blank as well.</P>

<A NAME="emacs"></A>
<H4><A NAME="12">emacs</A></H4>

<P>To use GNU Emacs (or its counterpart, XEmacs), there are really only
two commands you need to know. Heck, they're the only ones <I>I</I>
know.</P>

<P>While you're editing a certain file with <B>emacs</B> or <B>xemacs</B>,
you can save it with the <B><TT>[Ctrl]-x [Ctrl]-s</B></TT> keystrokes. Then to
exit, type <B><TT>[Ctrl]-x [Ctrl]-c</TT></B>.</P>

<A NAME="pico"></A>
<H4><A NAME="13">pico</A></H4>

<P>The instructions for using <B>pico</B> are located on the screen. You
save the file by using the <B><TT>[Ctrl]-o</TT></B> keystroke (for
write-<I>o</I>ut) and exit with <B><TT>[Ctrl]-x</TT></B>.</P>

<P>As a permanent solution, you probably don't want to use <B>pico</B>. It
lacks real power. Since I am such a wuss, however, I still have the bad
habit of using <B>pico</B> once in a while. Why? By pressing
<B><TT>[Ctrl]璲</TT></B> I can get entire paragraphs wrapped into a nice
justified block. I don't know how to do that with the other text
editors.</P>

<A NAME="vim"></A>
<H4><A NAME="14">vim</A></H4>

<P>Most modern distributions include <B>vim</B>, derived from the
infamously arcane Unix editor, <B>vi</B>. (It stands for <B>vi</B>
I<B>m</B>proved, as a matter of fact.)</P>

<P>Using <B>vim</B> is different in that there are several modes in which
you use it. To do actual editing of the files, press <B><TT>[ESC]
i</TT></B> (both separately). Then to save it, press <B><TT>[ESC] :
w</TT></B>. Escape, the colon, and &quot;w&quot; should be keyed in one
after the other. Finally, to quit, type <B><TT>[ESC] : q</TT></B>. The
same rules apply as in previous <B>vim</B> commands.</P>

<P>You can use &quot;w&quot; and &quot;q&quot; at the same time to enable
yourself to write to the file and then quit right afterwards. Just press
<B><TT>[ESC] : w q</TT></B>.</P>

<P>If you don't have <B>vim</B> installed, try <B>vi</B> instead.</P>

<!-- Editing section initial entry completed at ~ Wed Jun  9 22:07:27 PDT 1999 -->

<A NAME="MonitoringYourSystem"></A>
<H3><A NAME="15">Monitoring Your System</A></H3>

<P>An important part of system administration (especially with your own
system) is being able to know what's going on.</P>

<!-- Section on `tail' added ~ Wed Jun  9 20:15:33 PDT 1999 -->

<A NAME="tail"></A>
<H4><A NAME="16">tail</A></H4>

<P>The program <B>tail</B> allows you to follow a file as it is growing. Most
often, I use it to follow <TT>/var/log/messages</TT>. I do that by typing
<TT><B>tail -f /var/log/messages</B></TT>. Of course, you can use anything
else, including the other logs in <TT>/var/log/</TT>. Another file you may want
to keep an eye out for is <TT>/var/log/secure</TT>.</P>

<P>If you want to leave that running all the time, I recommend having some sort
of terminal program in X, logged in as root through <B>su</B>.</P>

<P>Another program you may want to look at is <B>head</B>. It monitors the top
of the file specified, instead of the bottom.</P>

<!-- Done with `tail' section. -->

<A NAME="top"></A>
<H4><A NAME="17">top</A></H4>

<P>This program shows a lot of stuff that goes on with your system. In 
the program, you can type:</P>

<OL>
<LI><B>M</B> for memory usage information</LI>
<LI><B>P</B> for CPU information</LI>
<LI><B>q</B> to quit</LI>
</OL>

<!-- This paragraph added on ~ Wed Jun  9 20:12:02 PDT 1999 -->

<P>Once you try it, you can see that <B>top</B> shows you the memory usage, uptime, load average, CPU states, and processes.</P>

<!-- Done with paragraph -->

<A NAME="w"></A>
<H4><A NAME="18">w</A></H4>

<P>Typing <B><TT>w</TT></B> will tell you who is logged in. This can be
helpful if you're the only one who uses your computer and you see someone
logged in that's not supposed to be.</P>

<P>Another alternative is <B>who</B>.</P>

<A NAME="ShuttingDownAndRebooting"></A>
<H3><A NAME="19">Shutting Down and Rebooting</A></H3>

<P>To shut down your system, type <B><TT>shutdown -h now</TT></B>, which
tells the <B>shutdown</B> program to begin system halt immediately. You
can also tell it to halt the system at a later time, I think, but you'll
have to consult the <B>shutdown</B> manual page for that (<B><TT>man
shutdown</TT></B>).</P>

<P>To do a reboot, you can either type <B><TT>reboot</TT></B> or
<B><TT>shutdown -r</TT></B>. You can also use the famous Ctrl-Alt-Delete
combination to reboot, which you might already be familiar with.</P>

<P>Shutting down and restarting properly (as described above) will prevent
your filesystem from being damaged. Filesystem damage is the most obvious
of the consequences, but there are probably other things out there that I
don't know about. The point is, shut down your system properly.</P>

<P>There are (rare!) cases in which the machine might lock up entirely,
and prevent you from being able to access a command prompt. Only then will
your last resort be to do a forced reboot (just pressing the restart
button on the case).</P>

<A NAME="books"></A>
<H3><A NAME="20">Related Books</A></H3>

<OL>
<LI><A HREF="http://www.amazon.com/exec/obidos/ASIN/1565924266/joshslinuxguide">Learning the VI Editor</A> - a book to teach you how to use the standard text editor for all Unix systems.
<LI><A HREF="http://www.amazon.com/exec/obidos/ASIN/1565921526/joshslinuxguide">Learning GNU Emacs</A> - another book on another powerful text editor. It's good especially if you program or simply prefer Emacs.
<LI><A HREF="http://www.amazon.com/exec/obidos/ASIN/0136805965/joshslinuxguide">Linux System Administration Handbook</A> - for those who are using their Linux box as a server</OL>

<HR>

<P><B><FONT SIZE="-1">Copyright &copy; 1997-1999 <A
HREF="mailto:[e-mail]">Joshua Go ([e-mail])</A>. All
rights reserved. Permission to use, distribute, and copy this document is
hereby granted. You may modify this document as long as credit to me is
given.</FONT></B></P>

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