...making Linux just a little more fun!

<-- prev | next -->

More 2 Cent Tips!

See also: The Answer Gang's Knowledge Base and the LG Search Engine


Asking 2c-tips of TAG

Thomas Adam (thomas_adam from bonbon.net)

I am a little bit concerned the people here (especially those that are more established) don't fully understand what constitutes a 2c-tip. A 2c-tip is just that -- something that is short and easy and can be done in a few steps. Asking whether it is appropriate (Neil!) just causes us more grief to wade through meta questions!

This might be in the form of a configuration tweak, or a minuture program that performs a given task, etc. Often though, larger tips are turned into TAG column entries -- and vice versa.

Often what would be flagged by Heather and I as a TAG entry might well form off-shoots to 2c-tips if the quality of the thread in question is not worthy.

But we will publish anything not only explicitly marked as a 2c-tip, but also what we deem appropriate to be one. We certainly don't filter out sent in tips -- only vary rarely. The only thing I will say to you is that don't always expect to submit one and see it in the next release of LG. Heather and I decide which tips get published when.

Send them in.... you know you want to.

-- Thomas Adam


Found It!

Becca Putman (sapphos from carolina.rr.com)
Question by RedHat Enigma List , (enigma-list from redhat.com)

Between these two lists, I figured my problem out. My TZ87 tape drive works perfectly under Linux. I found a product called vmsbackup that allows unix users to extract plain-text files from a VMS backup tape. If anyone else is interested in such a piece of arcana, it can be downloaded from http://vms.process.com/ftp/vms-freeware/FREE-VMS. I had to hack the code (can't use any other word than that, as I'm not a C coder at all) to eliminate certain files from being attempted. Once I did all that, every came off the tape nice and clean.

Next topic will be... smile

Thanks to everyone who has had input here - I really do appreciate the help!

Becca

[Ben] That's great, Becca - I'm glad to know that we could help, and like to hear success stories. Too bad more of the folks we help don't let us know the end result; a sense of completion is a pretty nice thing to have.
The main bulk of this thread appears in this month's TAG column, here:
Linux and SCSI tape drives

-- Thomas Adam


Question

Jose Garcia (quantum_usa from yahoo.com)
Answered By Kapil Hari Paranjape, Jim Dennis

Well, my problem is a little bit different. I'm building up a network at home and I want all computers with Windows 2000 and also Linux. Every computer is working ok with both operating systems, but the server. The two operating systems are installed already but, linux is not showing up. You go to the cmos setup and see Linus there in its own partition. But when the computer is booting, it doesn't show up and no way to boot from Linux. Now, even Windows is not showing up. After a few steps, [ counting memory, detecting drivesetc, it gets stuck ] Could you give me a hint to solve this?

[Kapil] I sense some serious confusion. How can the CMOS show you partitions, let alone Linus (I presume you mean Linux)? Even the BIOS setup doesn't know anything about the operating systems.
1. Try to use a rescue floppy (your created one at install time didn't you?!) to boot your system. If you don't have any such alternate method to boot the existing system you may have no choice but to re-install.
2. When you run a server, it doesn't really make sense to run two different O/Ses on it. How would the clients/users know before connecting what they could expect from the server?
[JimD]
Your question doesn't quite make sense. You can't see partitions or OS installations from your CMOS Setup. You can see drives.
So when you say things like: "linux is not showing up" and that you "see Linus[sic] there" and "it doesn't how up" it's not clear what you're looking at, where you're expecting to see it. You say that "you go to the cmos setup" but as I've said a normal BIOS setup doesn't display partitions and doesn't provide a list of installed or available OS' or other boot options.
So you must be looking at a bootloader (LILO, GRUB, System Commander, ChOS, NT's "Boot Manager" or something else. So, figure out which bootloader you're trying to use. You could also try booting from a rescue disk like Knoppix, Tom's Root/Boot, the LNX-BBC or whatever and using that to install a different boot loader like LILO.
It sounds like you'll need help with that, too. Without more details about which distribution you installed, the order in which you installed Linux and Win2K etc. (Hint: install Microsoft products first, then let Linux work around their settings).


Xserver spits multiple windows to foreign Xclient

Michiel Leegwater (mleegwt from conceptsfa.nl)
Answered By Kapil Hari Paranjape, Chris Gianakopoulos

Hi everyone,

Multiple people using the same machine configuration and it's programs is a wonderfull thing. Especially when the other people want to be at their own machine and not install linux on their machine. There Exceed starts to be very effective. So far so good.

Now the problem. I updated my pc from Mandrake 8 to 9.1(standard kernel). I had XDCMP Xclients working on MDK 8 before. That worked perfectly. Now I have xdm partially configured and I am able to login at the remote PC graphically, but then the server seems to be giving the client one screen/window for the desktop, one for each program and so on. I used to get one integrated thing completely filling the client PC's physical screen as if using Linux in stead of Windows with Exceed.

Anyone knowing what I have to change(or where to look) to get things identical to the "local" behaviour?

Does anyone know some place to find some good backgrounds on Xserver, Xfs and X in general?

Thanks for your time,

Michiel Leegwater

[Kapil] Let A be the client program (the "Xserver" which can be full screen or smaller) which in your case is Exceed.
Let B be the server system with which A is communicating which in your case is a GNU/Linux Mandrake machine.
B makes requests to A to create and destroy Xobjects; the actual placement, rendering and so on of these objects is a matter for A to decide.
So I do not think the problem you have given has to do with the Mandrake Server (B). Instead look at the configuration of the Exceed software (A).
Also have a look at the XWindow-Overview-HOWTO.
http://www.tldp.org/HOWTO/XWindow-Overview-HOWTO/index.html -- Thomas Adam

The very strange thing is I never changed the config of B. And after I did now the situation did not much improve(no improvement actually). Any more hints?

Because there's more than just xdm I also tried gdm, kdm and kde (editing /etc/sysconfig/desktop) Turning to kde or kdm has a strange extra effect logged in /var/log/messages:

Aug 11 19:46:10 obelix mdkkdm[8558]: Greeter exited unexpectedly
Aug 11 19:46:10 obelix mdkkdm[8558]: Abnormal helper termination, code 1,
signal 0
Aug 11 19:46:34 obelix mdkkdm[8567]: Greeter exited unexpectedly
Aug 11 19:46:34 obelix mdkkdm[8567]: Abnormal helper termination, code 0,
signal 11

Does anyone know why this happens??

[Chris] It's been a while. I used Exceed Version 7 for grins. If I recall, in the configuration options (I think it was screen), I had a choice between multiple windows or a single window. With multiple windows, you get the wonderful Microsoft background with a new window popping up with each application. With the single window choice, you see what you would if you were running X on the Linux machine.
For example, I set up Exceed to run in passive mode listening on port 6000. I then telnet into the Linux machine, set my DISPLAY name to refer to the appropriate host with window 0 (for example "export DISPLAY=nitro:0"), and might (from the telnet session) type "icewm &".
That's the way I do it. Hmmm.
I'm guessing that you might wanna see the graphical login, so, I am hoping that all you have to do is the single window selection thing, and things will work. I hope.
Regards,
Chris Gianakopoulos


Linux Filesystem

Joydeep Bakshi (joy12 from vsnl.net)
Answered By Faber Fedor, Benjamin Okopnik

Hi, I am a computer faculty & also teach Linux. I am interested to know about the advantage/disadv. & the difference of ext2,ext3 and the new Reiserfs file-system of linux. could any one please provide me these info. ? any link for further reading is also welcome.

[Faber] Have you read: http://www.tldp.org/HOWTO/Filesystems-HOWTO.html ?
[Ben] [blink] Joydeep... how do you do that if you're not familiar with even the very basics of finding information under Linux? I really don't envy your students the quality of information they're receiving. The above may sound harsh, but given the questions you've posted to this list over time - including this one - and the skills required for teaching (considered independently from the actual content), I find the above statement highly incongruous with your level of knowledge.
ReiserFS isn't what I'd call "new". You can find out about the various filesystems by looking at the relevant HOWTOs - the Filesystems-HOWTO, the ext3-(mini,usage)-HOWTOs - and the kernel documentation, usually available (if you have the kernel sources installed) in "/usr/src/kernel-source-<version>/Documentation/filesystems, with each type of supported FS having its own explanatory file.


partiton

John Savic (johnsavic from bettanet.net.au)
Answered By Karl-Heinz Herrmann

hi,

Ive just bought a new pc, and had the vendor load linux mandrake, as I = am not impressed with micoscum corp. I need to run mechanical desktop = which dosent seem to like linux, so can u please advise. talking to some boffins, I need to partition the drive, and set up = windows, can u please advise, and if this is the case, can u please = advise how to go about it, as I am a real novice at linux.

thankyou
john savic

[K.-H] well -- whatever mechanical desktop is, if its a win only application you'll need windows.
If it's not very hardware intensive you might get away in an emulator (e.g. wine). Then there is (commercial) vmware which runs a virtual PC inside linux (which can run windows). Or you change to a dual boot system Linux/win.
Dual boot system are best set up right from the beginning. Messing around with partitions after everything is installed is always risky. You can try (commercial) PartitionMagic to repartition. fips http://www.igd.fhg.de/~aschaefe/fips is a free version with a less fancy GUI I guess.
What partition layout would be useful (or possible) depends on how it is now and what you want. Usually I would put firs the win partition and then only the Linux partitions (note plural), often in an extended partition. If you've one huge Linux partition now I don't know if you can free the beginning -- it might be restricted to free the top end.
Well -- messing around (successfully) with partitions takes at least some knowledge of partitions on PC systems. This is not (very) specific to Linux, but of course all the Linux tool behave a little different from the old DOS tools (like fdisk, format,...).
There is a nice page giving hints how to ask questions which get answered/answered with something really helpful:
http://linuxgazette.net/tag/ask-the-gang.html
which also mentions the possibility to search on TAG or google for relevant search criteria: "linux partition resize" might be all that's needed.


PPP over parport?

Peter Paluch (peterp from frcatel.fri.utc.sk)
Question by linux-questions-only (linux-questions-only from linuxgazette.com)
Answered By Thomas Adam

Hello,

Originally it started as a non-Linux problem. I had to interconnect two Windows95 machines via a serial link using the Direct Cable Link function. However those machined refused to connect (of course, what else could I expect from M$ products...). After several hours of unsuccessful experiments I finally booted Linux on one of these machines and after five minutes of playing with pppd I had the Windows95 and Linux up-and-connected perfectly.

However, the serial link was too slow because of an old UART, so I thought of using a parallel cable instead, with Win95 at one side of the link and Linux at the another. But here I have a bigger problem. The Direct Cable Link in Windows always uses PPP protocol, no matter what type of cable it is used over. However, as it seems, the pppd daemon under Linux supports serial ports only. I could not force it into using the parallel port, neither lp0 nor parport0. This is the only answer I got from it:

Aug 2 14:20:44 gericom pppd[11246]: pppd 2.4.1 started by root, uid 0 Aug 2 14:20:44 gericom pppd[11246]: tcgetattr: Invalid argument(22) Aug 2 14:20:45 gericom pppd[11246]: Exit.

I did my Google homework but I couldn't find any clues how to use PPP protocol over parallel port under Linux and there is no mention of anything similar in the pppd documentation or source files.

Is it possible at all to run PPP over parallel cable under Linux? If yes, how should it be done?

I know there is PLIP but it won't work. Win95 really uses PPP even over parallel cable.

Thanks in forward.

Regards,
Peter

[Thomas] That's because you cannot. Alas, as your observations and in-depth research show, you can only use pppd over serial (in Linux anyhow).
I use PLIP all the time, although I have never had the need to use it to connect to windows, but that doesn't mean I don't know of a few things to try :)
Would you go as far as to allow DOS <-> Linux connection? There's a link on the PLIP-HOWTO.
http://www.tldp.org/HOWTO/PLIP.html
If it is Win95 connectivity you're after then I suggest a program called "kermit" which offers paralell line IP connectivity for windows.
HTH,
-- Thomas Adam


Help - trashed partition table

Mike Martin (The LG Answer Gang)
Answered By Jay R. Ashworth

Hi

Somehow I managed to trash my partition table on my RH system I rebooted and the kernel failed to find any partitons

So then I booted from my RH rescue disk

Then it could not find any partitions, so I did fdisk /dev/hda, and my partitions appeared to be there so I did w to write

Disaster - now in rescue mode there are no partitions at all

Anyone any ideas?

[Jay] Yeah; there's a program called gpart, that can sift the disk and find your partitions, and then reconstruct your ptable.
Check with Google.


VPN technology

emmanuel damons (emmanueldamons from yahoo.com)
Answered By Jay, R. Ashworth

Hi

I would like to setup a VPN network between my offices. I really would to stick to linux that ohter OS's .

What do you recommend I go with?

I have read some thing about PPTD would this be a could choice for me?

Thanks
Emmanuel

[Jay] PPTP, actually. The Microsoft Approved VPN -- which means don't use it unless you have to.
If this is for a business application, you might want to consider buying boxes -- the SnapGear's do both PPTP and IPSec, the other alternative, and they run Linux, which might make your life easier if you're a linux guy; I am, we resell them, and they Just Work. They start at about $250 a side, which is probably less than you'll pay yourself to set up IPSec on a pair of linux boxes, not to mention the time you'll spend tightening those two Linux boxen to be safe directly connected to the net.
If you really want to do it yourself, PPTP and IPSec are the two things to Google for.


Squid and FTP

qwert_zaq (qwert_zaq from ukr.net)
Answered By Thomas Adam

http://frox.sourceforge.net

frox, a transparent ftp proxy

This is the homepage of frox. It is a transparent ftp proxy which is released under the GPL. It optionally supports caching (either through an external http cache (eg. [1]squid), or by maintaining a cache locally), and/or running a virus scanner, on downloaded files. It is written with security in mind, and in the default setup it runs as a non root user in a chroot jail.

[Thomas] Cool, I like this! As I am resident on the Squid-Users mailing list, I have word that they developers do plan to allow FTP access at some point through Squid, but they're not sure when.


(no subject)

Thomas Adam (The LG Weekend Mechanic)

Nadia,

http://linuxgazette.net/tag/ask-the-gang.html

will tell you two things -- a) that the subject line of this e-mail is dismal, and b) you should send your e-mails to this list in PLAIN TEXT only and not HTML. If you look below betweeen the "---annoyance---" marker, that is a sample of how your e-mail has reached us. Hardly distinguishable.

However, to answer your question...

"Swap" refers to the term by which disk-space can be used as memory. Under Windows (Note Bene -- it is not a windows XP specific concept, but is generic over all windows'), this is represented by a file.

In Linux, however, this is represented by a partition (an area of disk that is "housed" by itself). This is then mounted at boot-time in /etc/fstab (assuming you have the correct entry). You can make a swap partition by doing...

mkswap /dev/hdxx && swapon

where /dev/hdxx is the device that you want to use for your swap.

It is also possible to share your windows swapfile with Linux. The following howto will help you with that:

http://www.linuxdocs.org/HOWTOs/mini/Swap-Space.html

although I wouldn't recommend it. Instead, I would go with a native swap partition.

HTH,

-- Thomas Adam


Uninstalling the files that get untared

Tim Millard (tmillard from voyager.net)
Answered By Ben Okopnik

I'm running Slackware 3.0 on a 486sx with 4MB of ram, and I want to install some tar archives. Here's my question:

After I have untared a file is there a way I can "undo" the changes that tar made?

I looked on freshmeat.net and could not find any "Install trackers." Perhaps I should download that RPM thing from Red Hat and just use that.

[Ben] Yep; fairly basic, in fact.
rm `tar tf tarfile.tar`
This, of course, assumes that the tar file is still in the same directory from which you untarred it, your UID and the directory/file permissions haven't been changed, etc. That is, if you just untarred it with:
tar xf tarfile.tar
then the above will get rid of the newly-created files.
<smile> Searching for specific software often requires more than just trying a single query and giving up, particularly when the phrasing of the query is not definitive. You should also take a look at "checkinstall" and "stow" for relevant solutions which you may find necessary later in the installation cycle - this assumes that you're installing a non-Slack tarball. I also suggest reading my "Installing Software from Source" article in LG#74; it deals with several important parts of this process.
If you're using Slackware, its default package manager (IIRC) is based on gzipped tar files. You really don't want to start messing with alternate package schemes until you're comfortable with the native one.
I just caught a hidden assumption in what I wrote, above - I was presuming that no existing files were overwritten by the untarring process. If you were to, e.g., untar a file that replaced your "/etc/passwd" and then "rm"ed the contents list as above, your system would become, erm, slightly less useful than formerly.
The standard solution is "don't do that, then." As I described in my article, you should untar into a directory reserved or created for the purpose, then make the decision about what gets installed vs. deleted, etc. Again, this is in regard to a "random" (meaning that it is not a part of your distribution) tarball; as with any piece of software you install on your system, you need to vet it carefully - something that is normally done for you in the distro packages. This strongly implies the above procedure; when you untar a file as root, particularly in '/', you're exposing your system to anything that the tarball author wants to do - including complete system takeover or erasure. /Caveat emptor/.


Setting up LANG (UTF-8 issue)

Ashwin N (yodha8 from yahoo.co.uk)

Hi all,

Recently there had been discussion on the method of switching off the UTF-8 LANG setting that is appearing in recent RedHat (and maybe other) distros.

The best way of turning this off for the whole system is by editing the file /etc/sysconfig/i18n

For setting it up for a particular user, create a file ~/.i18n and put the setting there.

ashwin


This page edited and maintained by the Editors of Linux Gazette
HTML script maintained by Heather Stern of Starshine Technical Services, http://www.starshine.org/

 

Copyright © 2004, . Released under the Open Publication license unless otherwise noted in the body of the article. Linux Gazette is not produced, sponsored, or endorsed by its prior host, SSC, Inc.

Published in Issue 103 of Linux Gazette, June 2004

Tux