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<?php
require_once('template.php');
page_header('Linux FAQ');
echo <<<END
<div id="content3">
This feature of the SLUG website is just getting started. We're not going to
answer all the question you have (there's a whole internet out there; go
look!) However, we can answer some of the more common questions, or direct
you to where they are best answered:
<P>
<UL>
<LI>
<A HREF="./distros.html">
What's the best Linux distribution?
</A>
<LI>
<A HREF="#dos">
What are the differences between Linux and DOS commands?
</A>
<LI>
<A HREF="#reboot">
My Linux system says I didn't mount my filesystem cleanly. What do I do?
<BR>
What does this <EM>maximum mount count</EM> mean?
</A>
<LI>
<A HREF="#floppy">
I can't make mount/copy files to my floppy unless I'm root. How do I get around
this?
</A>
<LI>
<A HREF="#links">
What are <STRONG>links</STRONG>? And what's the difference between
a <STRONG>hard link</STRONG> and a <STRONG>soft link</STRONG>?
</A>
<LI>
<A HREF="#ppp">
How do I set up PPP? None of the other programs I tried worked.
</A>
<LI>
<A HREF="#rr1">
How to I set up with RoadRunner?
</A>
<LI>
<A HREF="#rr2">
Can I set up a network where RoadRunner runs on one machine, but
the other machines can access the internet through RoadRunner as well?
</A>
<LI>
<A HREF="#console1">
How do I get from the console to an X-Window session?
<BR>
How do I get from an X-Window session to a console?
</A>
<LI>
<A HREF="#console2">
Can I get more consoles? How?
</A>
<LI>
<A HREF="#autofs">
What is autofs/automount, and how do I make it work?
</A>
<LI>
<A HREF="#keyswap">
How do I swap Caps Lock and Control on my keyboard?
</A>
<LI>
<A HREF="#smbprint">
How do I print to a Windows printer from my Linux box?
</A>
<LI>
<A HREF="#init">
How do init scripts work and what are they?
</A>
<LI>
<A HREF="./permissions.php">
I don't understand <I>permissions</I>. Can you help?
</A>
<LI>
<a href="#procmail">
When I hit "Reply" to an email list I'm on, it replies to the person who
wrote the email, not the list. How do I fix this?<br>
On some email lists, I can't tell from the subject line that the mail is
coming from a list. Is there any way to handle this?
</a>
<LI>
<a href="#dupemails">
I keep getting all these duplicate emails. While I'm getting the problem
fixed, is there a way to turn them off?
</a>
<li>
<a href="#idetape">
How do I get my IDE/ATAPI tape drive working?
</a>
<li>
<a href="#time">
How do I set the time on my computer?
</a>
<li>
<a href="#irqs">
What's the deal with IRQ/DMA/IO Addresses?
</a>
<LI>
<A HREF="#nice">
What's the difference between the nice value and the priority value in the
top program? When I change the nice value to X to reduce the impact of a process
on system performance, the priority goes up to X as well. Should I change the
priority to a lesser value or should it do it on its own when I increase the
nice value?
</A>
<LI>
<A HREF="#superblock">
What's a "super block"? How do you fix it with fsck? Can you?
</a>
<LI>
<A HREF="#blanking">
How do I turn off screen blanking at the console?
</a>
<LI>
<A HREF="#iptables">
Where's that dang IPTABLES script by Derek I keep hearing about?
</a>
</UL>
<P>
Do you have other questions you'd like to see answered?
<A HREF="mailto:[email protected]">Let us know</A>. We can't guarantee
we'll answer them, but you'll never know unless you ask!
<!-- START OF ANSWERS -->
<HR>
<A NAME="autofs"></A>
<h4>Question</h4>
What is autofs/automount, and how do I make it work?
<P>
<h4>Answer</h4>
<p>
Normally in Linux, things like floppy disks, CD-ROMs and such have to be
manually "mounted". This means that you associate a directory on your hard
drive with that device, and you can then read and/or write to the device.
(Note I did not say that you <EM>copy</EM> the contents to the directory;
this isn't necessary, and it's not what you do.)
<P>
With automount/autofs, Linux does the mounting work for you. For instance,
if properly configured, you can just pop a floppy in and read it, like in
DOS or Windows.
<P>
The first step in using autofs is picking a directory to mount to. You could
make a directory off of the root directory, called <STRONG>auto</STRONG> if you
like. But more common practice is to find the <STRONG>/mnt</STRONG> directory and
make a directory off of that. If you're mounting a floppy, it could be
something like <STRONG>/mnt/floppy</STRONG>.
<P>
Here's a table of devices for a typical system:
<P>
<TABLE BORDER="1" COLS="4">
<TR COLSPAN="4">
<TH>Media</TH>
<TH>Device</TH>
<TH>Filesystem</TH>
<TH>Mount Point</TH>
</TR>
<TR COLSPAN="4">
<TD>Hard Drive</TD>
<TD>/dev/hda1</TD>
<TD>FAT32</TD>
<TD>/mnt/win</TD>
</TR>
<TR COLSPAN="4">
<TD>CD-ROM</TD>
<TD>/dev/cdrom</TD>
<TD>iso9660</TD>
<TD>/mnt/cdrom</TD>
</TR>
<TR COLSPAN="4">
<TD>Floppy</TD>
<TD>/dev/fd0</TD>
<TD>EXT2</TD>
<TD>/mnt/floppy</TD>
</TR>
<TR COLSPAN="4">
<TD>Floppy</TD>
<TD>/dev/fd0</TD>
<TD>FAT</TD>
<TD>/mnt/dos</TD>
</TR>
</TABLE>
<P>
Notice how, for the single floppy drive, I have created two theoretical
mount points. This is because I want to mount it differently based on
whether it's a native floppy or a DOS floppy.
<P>
Okay, now comes the configuration files. The first is
<STRONG>/etc/auto.master</STRONG> which
describes which empty directory I am using, a pointer to the configuration
file for that directory, and any options. In my case the only option is a
timeout of 5 seconds:
</p>
<PRE>
/mnt /etc/auto.mnt --timeout 5
</PRE>
<P>
Here's how the timeout works: When I <STRONG>cd</STRONG> into /mnt/cdrom the system
will check to see if something is mounted there. If not, autofs will take over
and attempt a mount. If it failes, <STRONG>cd</STRONG> fails. If it is successful,
<STRONG>cd</STRONG>
is successful and the CD-ROM is mounted. Now, as long as I am in
<STRONG>/mnt/cdrom</STRONG> somewhere the device is being used. Once I am
done I can <STRONG>cd</STRONG>
back out and autofs will wait 5 seconds to see if anything else needs to
access the mount point before unmounting it.
<P>
With that said, here's the last configuration file,
<STRONG>/etc/auto.mnt</STRONG>:
<P>
<PRE>
cdrom -fstype=iso9660,rw :/dev/cdrom
floppy -fstype=ext2,rw :/dev/fd0
dos -fstype=msdos,rw :/dev/fd0
win -fstype=vfat,rw :/def/hda1
</PRE>
<P>
You can now enable autofs at boot time and things will be running great. As
quickly as I've said that, though, you'll end up running into trouble.
It's inescapable. Remember, you don't have to have support compiled in
for all these filesystem types, but you should have them as loadable
modules. Do, however, compile in all those <STRONG>codepage</STRONG>
things in the filesystems area of the kernel config. You need two of
them to be able to work with iso9660 and vfat, but I've forgotten which ones.
;)
<P>
If all of that <EM>still</EM> fails, go and edit your
<STRONG>/etc/syslog.conf</STRONG> and add a line:
<P>
<PRE>
*.debug /var/log/debug
</PRE>
<P>
which autofs uses-- among other programs-- to output its debugging
information. You can attempt to use autofs a few times, look in that
file, and see what's going on. (Remember to delete this entry once you
are done, though.) As root, just
<PRE>
killall -HUP syslogd
</PRE>
for the changes to take affect.
<P>
Well, that's about it. My primer on autofs based on my experiences. Hope
this helps. :)
<P>
<STRONG>Paul Braman</STRONG>
<HR>
<A NAME="console1"></A>
<h4>Question</h4>
<P>
How do I get from the console to an X-Window session?
<BR>
How do I get from an X-Window session to a console?
<h4>Answer</h4>
<P>
Assuming you have X-Window running....
<P>
When switching between text-mode consoles (VC or "virtual console"), you
merely need to use the ALT modifier (ALT-F1 through ALT-F7).
<P>
While running an X server, you use the CTRL-ALT modifer to get
<EM>out</EM> of X and back to a text-mode VC (CTRL-ALT-F1 through
CTRL-ALT-F6). Also, CTRL-ALT-BACKSPACE will kill X altogether,
and CTRL-ALT-KEYPAD+ and CTRL-ALT-KEYPAD- will switch between
available resolutions.
<P>
<STRONG>Ian C. Blenke</STRONG>
<HR>
<A NAME="console2"></A>
<h4>Question</h4>
Can I get more consoles? How?
<h4>Answer</h4>
<P>
As XFree86 allocates your "last available <A HREF="./definitions.html#console">
VC</A>", and VCs 1 through
6 are in use by most distributions, VC 7 is typically allocated
by X when it starts (thus F7). If you start multiple X servers,
each one will take a progressive VC (F8, F9, etc.)
<P>
Here are a few quick tricks that I've used for quite some time:
<P>
<STRONG>Trick #1:</STRONG>
<P>
One trick I find useful is to open up a master syslog on VC 12,
and use ALT-F12 to get to it. I've been using it so long, it's
the first thing I do to a Linux install when I'm finished. To
do this, merely do this:
<P>
<PRE>
echo '*.* /dev/tty12' >> /etc/syslog.conf
</PRE>
<P>
Or, add "*.*" followed by whitespace (tabs and spaces), followed
by "/dev/tty12" to /etc/syslog.conf
<P>
If you start/stop syslog (or even, egads, reboot), you should
have a VC #12 that keeps up with all of your latest syslog events.
<P>
<PRE>
/etc/rc.d/init.d/syslog stop
/etc/rc.d/init.d/syslog start
</PRE>
<P>
or, for newer distributions with the improved SYSV init scripts:
<P>
<PRE>
/etc/rc.d/init.d/syslog restart
</PRE>
<P>
Also, on older distributions, VCs /dev's past tty8 are typically
"missing". To create the /dev device files, do the following:
<P>
<PRE>
cd /dev
./MAKEDEV tty12
</PRE>
<P>
If you wish, you can repeat this for any number of tty's. Take
a look at the source to /dev/MAKEDEV - it's a wonderfully simple
shell script.
<P>
<STRONG>Trick #2:</STRONG>
<P>
After you've created all of these extra VCs, wouldn't it be nice
to actually <EM>use</EM> them? If you a CLI purist like me, occasionally
the overhead of X really grinds on your nerves. Just because
most distributions only offer VC logins from tty1 through tty6
doesn't mean you can't add a few more.
<P>
The key to adding more VCs is /etc/inittab. This is the config
file for /sbin/init (pid #1!), so be <STRONG>very</STRONG> careful when editing
this file, or you might accidentally render your machine either
unusable or even <STRONG>unbootable</STRONG>. Caveat emptor!
You have been warned!
<P>
Seriously, however, it really is quite safe and easy if you are
careful. Typically, you will find the following VC handlers in
/etc/inittab:
<P>
<PRE>
1:2345:respawn:/sbin/mingetty tty1
2:2345:respawn:/sbin/mingetty tty2
3:2345:respawn:/sbin/mingetty tty3
4:2345:respawn:/sbin/mingetty tty4
5:2345:respawn:/sbin/mingetty tty5
6:2345:respawn:/sbin/mingetty tty6
</PRE>
<P>
To extend available consoles to tty7 (F7) through tty10 (F10),
merely add the following lines to your inittab:
<P>
<PRE>
7:2345:respawn:/sbin/mingetty tty7
8:2345:respawn:/sbin/mingetty tty8
9:2345:respawn:/sbin/mingetty tty9
10:2345:respawn:/sbin/mingetty tty10
</PRE>
<P>
Make sure that /dev/tty7 through /dev/tty10 exist (using the
MAKEDEV fix above if they are missing), and you're almost
there! If you signal to init to reread /etc/inittab (or,
ack, even reboot), the changes will take effect and the
logins will appear on those VCs:
<P>
<PRE>
/sbin/init q
</PRE>
<P>
This forces init to check /etc/inittab and make appropriate
changes. WHATEVER YOU DO, DO NOT KILL PROCESS #1 DIRECTLY. :)
<P>
<STRONG>Tip:</STRONG> If you still decide to use X, you can still switch back,
just remember your last assigned VC in /etc/inittab - and
switch back to the NEXT VC. For example, if you have gettys
running on tty1 through tty10, tty11 will be your X session
and can be reached by using ALT-F11.
<P>
<STRONG>Trick #3:</STRONG>
<P>
The VCs don't end at F12. In fact, there are 63 available
virtual consoles (no longer a compile time parameter like
the older kernels used :) You can use F13 through F24 and
still directly access them by using the right-ALT key
modifier (RIGHTALT) instead of the left-ALT key along with
one of the function keys! What would be F13 is now
RIGHTALT-F1, and so on.
<P>
For example, add the following line to your inittab:
<P>
<PRE>
13:2345:respawn:/sbin/mingetty tty13
</PRE>
<P>
To switch to that VC, use RIGHTALT-F1. Neat stuff, that.
<P>
But the wonder doesn't stop there. You can cycle through
VCs by using the arrow keys as well. Give ALT-LEFTARROW
and ALT-RIGHTARROW a try at a textmode VC and you will
walk back and forth along the available VC sessions.
<P>
Looking through the FAQs, it looks like they have all of
this covered in the Keyboard-and-Console-HOWTO (check
/usr/doc/HOWTO/Keyboard-and-Console-HOWTO). They give
examples of how to implement truely dynamic gettys that
preclude the use of inittab to statically spawn sessions
that you may never use.
<P>
I hope that the above examples help some of the beginners
give a few new things a try.
<P>
<STRONG>Ian C. Blenke</STRONG>
<HR>
<A NAME="keyswap"></A>
<h4>Question</h4>
How do I swap the Caps Lock and Control keys?
<P>
<h4>Answer</h4>
<P>
<i>Note: this only works in the console, <b>not</b> in X Windows.</i>
First, understand that when <a href="./definitions.html#init"><strong>init</strong></a>
runs, it defines and loads the keyboard layout by looking in setup files or its own
init scripts. Since init scripts vary from distribution to distribution, you'll have to
do some detective work to find out how it works on your system.
<p>
Log in or su as root. (Otherwise you won't have access to the directories and files
you need.)
<p>
For Red Hat systems, the keyboard layout files are in the
/usr/lib/kbd/keymaps/i386/qwerty directory (assuming you're on a PC and using a
standard keyboard). These are tarballs, which you will have to unzip, edit and
rezip. To find which keymap is being used, look at the /etc/sysconfig/keyboard file.
In it, you will see a line that looks like:
<pre>
KEYTABLE="us"
</pre>
<p>
This tells you there is a file in /usr/lib/kbd/keymaps/i386/qwerty called
<i>us.kmap.gz</i>. This is the file you have to edit. Do the following
<pre>
cd /usr/lib/kbd/keymaps/i386/qwerty
gunzip us.kmap.gz
vi us.kmap
</pre>
<p>
(Use whatever editor you like.) Find the line that says something about keycode 29. It
probably says "Control" in it. Change this to "CapsLock". Now find the line that says
something about keycode 58. This probably says "CapsLock". Change that to "Control".
Save the file.
<p>
Recompress the file:
<pre>
gzip us.kmap
</pre>
<p>
At this point, you can reboot and the change will take effect. However, if you don't
want to go that far, you can run the following command in every console where you want
the change to take effect:
<pre>
loadkeys us
</pre>
<p>
For SuSE 6.1 systems, the keymap files are in the same place, but editing that keymap
may not do the trick. If it doesn't, look for a file named
/usr/src/linux/drivers/char/defkeymap.map and edit that file as well.
<h4>Paul M. Foster</h4>
<HR>
<A NAME="ppp"></A>
<h4>Question</h4>
How do I set up PPP on my computer? The other program I tried didn't work.
<P>
<h4>Answer</h4>
There are a myriad of programs out there to make ppp work on your system.
The answer below is just one way.
<P>
PPP requires several things to work properly. Two of them are the programs
<STRONG>pppd</STRONG> and <STRONG>chat</STRONG>. You
can find out if you have these by running
<PRE>
which pppd
which chat
</PRE>
<p>
If you get a response on both items, then the programs exist on your
system. Most likely, they will be in the <STRONG>/usr/sbin</STRONG>
directory.
<P>
First, you must create a script to get you online, which we'll call
<STRONG>pon</STRONG>. The script may be anywhere in your path, but best
location is probably <STRONG>/usr/local/bin</STRONG>. This will be the
program you run to get you one the internet. The script should
look something like this:
<hr>
<PRE>
#!/bin/sh
# This is a shell script to call Concentric (my isp).
# It requires some other files to work properly:
# /etc/ppp/peers/concentric
# /etc/ppp/options-concentric
# /etc/ppp/chat-concentric
# set up ppp connection in the background
/usr/sbin/pppd call concentric &
# tell the user when ppp is set up
echo Checking PPP connection...
while ! [ -e /var/run/ppp0.pid ]
do
sleep 1s
done
echo PPP connection is now set up!
</PRE>
<hr>
<p>
Next you need an <EM>peer</EM> file. This one will be called <STRONG>
/etc/ppp/peers/concentric</STRONG>.
<hr>
<PRE>
/dev/modem
57600
crtscts
lock
name "myloginname"
noipdefault
defaultroute
debug
noauth
connect '/usr/sbin/chat -v -f /etc/ppp/chat-concentric'
file /etc/ppp/options-concentric
</PRE>
<hr>
<p>
Of course, you can see that you will have to edit this file to put
<EM>your</EM> login name where "myloginname" is. If you want to enable
<EM>dial on demand</EM>, you can insert the word <EM>demand</EM> anywhere
above, and ppp will not start immediately when you call <EM>poff</EM>;
instead, it will wait until you ping or try to surf before it actually
starts.
<P>
Next you need a <STRONG>/etc/ppp/chat-concentric</STRONG> file. (Again, you
can change the filename, so long as you make the change in the <STRONG>pon
</STRONG> script as well.)
<hr>
<PRE>
TIMEOUT 60
ABORT "NO CARRIER"
ABORT BUSY
ABORT "NO DIALTONE"
ABORT ERROR
"" +++ATZ
OK ATDT5551212
CONNECT ""
</PRE>
<hr>
You'll have to edit the phone number to match the dialup number of your ISP
in the above file.
<P>
Next, you need a <STRONG>/etc/ppp/options-concentric</STRONG> file:
<HR>
<PRE>
/dev/modem
57600
crtscts
lock
name "myloginname"
noipdefault
defaultroute
debug
</PRE>
<HR>
And you'll have to edit <EM>myloginname</EM> as before.
<P>
And you'll need a file called <STRONG>/etc/ppp/pap-secrets</STRONG>.
This assumes that your ISP uses PAP authentication.
<HR>
<PRE>
myloginname * mypassword
</PRE>
<HR>
You will need to edit the login name and password in this file.
<P>
Lastly, you need a file called <STRONG>poff</STRONG>. You run this program
when you're done surfing or getting your email, and you want to log off. The
script looks like this:
<HR>
<PRE>
#!/bin/sh
#
# terminate a ppp connection
#
if [ "$1" = "" ]; then
DEVICE=ppp0
else
DEVICE=$1
fi
if [ -r /var/run/\$DEVICE.pid ]; then
kill -INT `cat /var/run/\$DEVICE.pid`
if [ ! "$?" = "0" ]; then
rm -f /var/run/\$DEVICE.pid
echo "ERROR: Removed stale pid file"
exit 1
fi
echo "PPP link to \$DEVICE terminated."
exit 0
fi
#
# The ppp process is not running for ppp0
#
echo "ERROR: PPP link is not active on \$DEVICE"
exit 1
</PRE>
<HR>
That's about as simple as I can make it.
<P>
<STRONG>Paul M. Foster</STRONG>
<HR>
<A NAME="rr1"></A>
<h4>
Question
</h4>
<P>
How do I set up RoadRunner?
<h4>Answer</h4>
<P>
There are various ways to do this. The following seems to be the most
trouble-free. (Your machine will have to be running
<STRONG>ipchains</STRONG> or <STRONG>ipfwadm</STRONG>, depending on your
distribution, and a dhcp client, such as <STRONG>dhcpcd</STRONG>.
<p>
<STRONG>Step 1</STRONG>
<P>
Find your <STRONG>/etc/resolv.conf</STRONG> file, make sure you have the
following line in it (assuming 24.92.0.68 is your nameserver; contact
RoadRunner to find the exact address):
<PRE>
search tampabay.rr.com
nameserver 24.92.0.68
</PRE>
<P>
<STRONG>Step 2</STRONG>
<P>
The following is a script you can run at boot time. Note that you will need
to edit this script before using it.
<PRE>
# change eth1 to be whatever your ethernet
# interface is...
# if you only have one ethernet card in the machine,
# it will probably be eth0
dhcpcd eth1
sleep 20
/sbin/ipfwadm -F -p deny
# the 192.168.1.0 is a mask for the local network
# change it to your local net quad
# and put a zero in the last section
/sbin/ipfwadm -F -a m -S 192.168.1.0/24 -D 0.0.0.0/0
</PRE>
If you have ipchains instead of ipfwadm, use the following instead of the
ipfwadm commands above. Likewise, be sure to edit them for your particular
local internet addresses.
<PRE>
ipchains -F forward
ipchains -P forward DENY
ipchains -A forward -s 192.168.0.0/16 -j MASQ
</PRE>
<P>
<STRONG>Ed Centanni</STRONG>
<HR>
<A NAME="rr2"></A>
<h4>
Question
</h4>
<P>
Can I set up a network where RoadRunner runs on one machine, but
the other machines can access the internet through RoadRunner as well?
<h4>Answer</h4>
<P>
<OL>
<LI>Build yourself a machine with two NICs.
<LI>Install Linux.
<UL>
<LI>Configure one interface (eth0) with an internal "private" static IP
(use something like 10.0.0.1, 172.16.0.1, 192.168.0.1, etc).
<LI>Configure the other interface (eth1) to use DHCP.
</UL>
<LI>Make sure you have ipfwadm or ipchains installed from your distribution.
<UL>
<LI>ipfwadm for 2.0.x kernels
<LI>ipchains for 2.2.x kernels
</UL>
<LI>Build a kernel with IP Masquerading support (if your kernel doesn't
already support it).
<LI>Turn on your system's IP Forwarding at boot time.
<UL>
<LI>Redhat servers: /etc/sysconfig/network - FORWARD_IPV4="yes"
<LI>others add: echo 1 > /proc/sys/net/ipv4/ip_forward
</UL>
<LI>Turn on masquerading.
<UL>
<LI>ipchains (you only need one of the three MASQ lines below)
<UL>
<LI>ipchains -F forward
<LI>ipchains -P forward DENY
<LI>ipchains -A forward -s 10.0.0.0/8 -j MASQ
<LI>ipchains -A forward -s 172.16.0.0/12 -j MASQ
<LI>ipchains -A forward -s 192.168.0.0/16 -j MASQ
</UL>
<LI>ipfwadm (you only need one of the three masquerade lines below)
<UL>
<LI>ipfwadm -F -p deny
<LI>ipfwadm -F -a masquerade -S 10.0.0.0/8 -D 0/0
<LI>ipfwadm -F -a masquerade -S 172.16.0.0/12 -D 0/0
<LI>ipfwadm -F -a masquerade -S 192.168.0.0/16 -D 0/0
</UL>
<LI>Configure your other PCs with IP addresses.
<UL>
<LI>On same subnet as the private (eth0) interface on your Linux server.
<LI>Pointing their default gateways at the Linux server.
</UL>
</UL>
</OL>
<h4>Troubleshooting</h4>
<UL>
<LI>If you can ping things on the 'net by IP but can't resolve:
<UL>
<LI>
<STRONG>Your DNS is broken</STRONG>. Work on /etc/resolv.conf and
/etc/nsswitch.conf.
<LI>
If your DNS is broken, <STRONG>your DHCP client is probably broken as
well</STRONG>
</UL>
<LI>If you can't ping things on the internet by IP address
<UL>
<LI><STRONG>Make sure your DHCP client is working right</STRONG>.
</UL>
<LI>RedHat 5.x uses DHCPD
<UL>
<LI>If you have a 2.2 kernel, you need DHCPD 1.3+
<LI>RedHat 6.0 uses PUMP.
<LI>Be sure to "update" your dist to the latest version of pump.
</UL>
<LI>If you run a named (bind) server on your Linux server, you can point your
other clients at it.
<LI>If you don't, merely point your client PCs at the roadrunner DNS server
(seems typically to be 24.92.0.58, but you can use any DNS server on the
internet).
</UL>
<h4>Ian C. Blenke</h4>
<HR>
<A NAME="smbprint"></A>
<h4>Question</h4>
How do I print to a Windows printer from my Linux box?
<h4>Answer</h4>
In your <STRONG>/etc/printcap</STRONG> file, you'll need to ensure you have
the following lines:
<PRE>
remote|remote-smbprinter:\
:lp=/dev/null:sh:\
:sd=/var/spool/lpd/stcolor-letter-ascii-mono-360:\
:if=/usr/local/samba/smbprint2:
</PRE>
<P>
The line that starts with <STRONG>:sd</STRONG> above is the spool directory
for your particular printer. You will need to find that directory and
substitute that for what is above.
<P>
You'll also notice the <STRONG>:if</STRONG> line above. This specifies an
input filter file for your printer. Here you specify the file <STRONG>
smbprint2</STRONG>. Below is that file (note: you may need to edit it):
<P>
<HR>
<PRE>
#!/bin/sh -x
# This script is an input filter for printcap printing
# on a unix machine. It uses the smbclient program to
# print the file to the specified smb-based server and
# service. For example you could have a printcap entry
# like this
#
# smb:lp=/dev/null:\
# sd=/usr/spool/smb:\
# sh:if=/usr/local/samba/smbprint
#
# which would create a unix printer called "smb" that
# will print via this script. You will need to create
# the spool directory /usr/spool/smb with
# appropriate permissions and ownerships for your system.
# Set these to the server and service you wish to print
# to. In this example I have a WfWg PC called "lapland"
# that has a printer exported called "printer" with no
# password.
#
# Script further altered by [email protected]
# (Michael Hamilton) so that the server, service, and
# password can be read from a
# /usr/var/spool/lpd/PRINTNAME/.config file.
#
# In order for this to work the /etc/printcap entry
# must include an
# accounting file (af=...):
#
# cdcolour:\
# :cm=CD IBM Colorjet on 6th:\
# :sd=/var/spool/lpd/cdcolour:\
# :af=/var/spool/lpd/cdcolour/acct:\
# :if=/usr/local/etc/smbprint:\
# :mx=0:\
# :lp=/dev/null:
#
# The /usr/var/spool/lpd/PRINTNAME/.config file
# should contain:
# server=PC_SERVER
# service=PR_SHARENAME
# password="password"
#
# E.g.
# server=PAULS_PC
# service=CJET_371
# password=""
#
# Debugging log file, change to /dev/null if you like.
#
logfile=/tmp/smb-print.log
# logfile=/dev/null
#
# The last parameter to the filter is the accounting
# file name.
# Extract the directory name from the file name.
# Concat this with /.config to get the config file.
#
eval acct_file=\\\${\$#}
spool_dir=`dirname \$acct_file`
config_file=\$spool_dir/.config
# Should read the following variables set in the
# config file:
# server
# service
# password
eval `cat $config_file`
#
# Some debugging help, change the >> to > if you
# want to save space.
#
echo "server \$server, service \$service" >> \$logfile
# smbprint \$@
(
# NOTE You may wish to add the line `echo translate'
# if you want automatic CR/LF translation when
# printing.
# echo translate
echo 'print -'
cat
) | /usr/bin/smbclient "\\\\\$server\\\$service" \
\$password -U \$server -N -P >> \$logfile
</PRE>
<P>
<STRONG>
Ed Centanni
</STRONG>
<HR>
<A NAME="dos"></A>
<h4>Question</h4>
What are the differences between Linux and DOS commands?
<h4>Answer</h4>
If you're familiar with DOS, it shouldn't take too long to become familiar
with Linux. Many of the commands are the same or similar. Here's a table of
commands that are correspond to each other in DOS and Linux:
<P>
<DIV ALIGN="CENTER">
<TABLE BORDER="1" CELLPADDING="5" CELLSPACING="5">
<TR>
<TH>DOS Version</TH>
<TH>Linux Version</TH>
<TH>Meaning</TH>
</TR>
<TR>
<TD>
;
</TD>
<TD>
<EM>
:
</EM>
</TD>
<TD>
separate directories in path
</TD>
</TR>
<TR>
<TD>
/
</TD>
<TD>
<EM>
-
</EM>
</TD>
<TD>
indicates command line parameters
</TD>
</TR>
<TR>
<TD>
\
</TD>
<TD>
<EM>
/
</EM>
</TD>
<TD>
separates subdirectories in file names
</TD>
</TR>
<TR>
<TD>
|
</TD>
<TD>
|
</TD>
<TD>
send output of one command to input of another ("pipe")
</TD>
</TR>
<TR>
<TD>
%PATH%
</TD>
<TD>
<EM>\$PATH</EM>
</TD>
<TD>
your path statement
</TD>
</TR>
<TR>
<TD>
attrib
</TD>
<TD>
<EM>chmod</EM>
</TD>
<TD>
change attributes (ownership) of a file
</TD>
</TR>
<TR>
<TD>
cd
</TD>
<TD>
cd
</TD>
<TD>
change directories
</TD>
</TR>
<TR>
<TD>
chdir
</TD>
<TD>
chdir
</TD>
<TD>
change directories
</TD>
</TR>
<TR>
<TD>
cls
</TD>
<TD>
<EM>clear</EM>
</TD>
<TD>
clear the screen
</TD>
</TR>
<TR>
<TD>
copy
</TD>
<TD>
<EM>cp</EM>
</TD>
<TD>
copy file(s)
</TD>
</TR>
<TR>
<TD>
date
</TD>
<TD>
date
</TD>
<TD>
change or show the date