Clueless at the Prompt Issue 17

"Linux Gazette...making Linux just a little more fun!"

CLUELESS at the Prompt: A Column for New Users

By Mike List, [email protected]

Welcome to installment 4 of Clueless at the Prompt: a new column for new users.

Connecting to a Second ISP...or Third, or

I recently got e-mail from a guy who wanted to know how to connect to a second ISP.His e-mail address apparently wasn't valid, and it got bounced back several times. Just as well, since I didn't have the answer at that point. Well, I got this idea, and I tried it and it works.Here's the deal: First,

 cp /usr/sbin/ppp-on to /usr/sbin/ppp-on.anysuffix

Then open the file you just created with a text editor, and change any information that applies to the secondary ISP, eg. dialup, the IP number of the ISP, username and password. write the file(save it) and try your new executable, ppp-on.anysuffix. Just a quick pointer, you could call your new script any name you want as long as there's no other file with the same name in your path,preferably no other file with the same name at all

Dealing With a Dynamic IP

These days most Internet Service Providers assign you a Dynamic IP when you logon to their network, due to the cost of assigning every customer a static IP. At present there are only so many IP addresses available and, apparently each one costs to register. Consequently ISPs buy a pool of IP addresses within a range and assign an available one at login. For most uses, such an arrangement is no problem, assuming that most internet usage consists of interaction between the ISP's computer and the local one. For some purposes, however such as allowing telnet or ftp to your computer the dynamic scheme is less than ideal. Here's a relatively painless way to get your current IP, so you can run with the big dogs. Open an xterm, or rxvt and type:

 ifconfig

which will bring up some info in two blocks. You'll want to note the bottom block, which will have a line that specifies your inet address expressed numerically. It will be in a xxx.xxx.xxx.xxx format, which corresponds to the standard IP address, in fact that's what it is. you ca write this number down or just highlight this IP address(to paste it)and type:

nslookup the.num.ber.

the number being your inet address from the last step. It may take a couple of minutes, but you will get a two line messagethat looks like:

Name:   your Fully Qualified Domain Name
                Address: IPa.ddr.ess.!!!

we may talk about FQDN some more another time, but for the purpose at hand, just type:

hostname Name

where Name is the first line from the above step. That's it, except that you must repeat this procedure every time you connect to your ISP. You might be able to write a script to automate this procedure, but in the meantime which as my friend Al used to say "is a groovy time", you can use this knowledge to run remote X apps(just a minute,I'm coming to that) allow your friends or inet associates to telnet to your computer, or ftp files from a telnetted site(this too, momentarily).What you need to know is that the next time youreboot, you may get a message saying that your computer name is "bad". This isn't a comment on your lack of originality or taste, and you should basically ignore it.

Using your Domain Name

If you have a shell account at a computer located at a university or school near you, this will amaze you. Oh yeah not, by way of a plug, but there is a semi commercial telnet box called linuxware.com(you will have to look up the URL yourself semi- plug, you might say, I'm a subscriber) What am I talking about? Using X to run apps from the remote computer on your screen. You can actually run a program that isn't installed on your computer, in X with the remote computer supplying the program. I think it embodies the essence of networking, with permissions set right, you can co-author a document, play a multi-user game (MUD)use a talkprogram, like ytalk, or do office or school work from your home computer.Here's what you need to do. First, you need to know and have your FQDN listed by typing:

hostname

as detailed above. If you have a static IP address, you can skip this step.What needs to be done next is to type:

xhost + the.telnet.box

When you hit enter you will see a message like, "the.telnet.box has been added to the control list". You will probably have to restart your window manager, your mileage may, as they say, vary. Now when you start a telnet session, you can enter the name of an X application and in a moment, the application window will apear on your screen, even if you don't have it installed on your computer. Do your work, play your game, and marvel at the ramifications of this capability.

You can also invite friends and coworkers over to your computer to do some work, socialize or learn something, in the following manner. Obtain your FQDN, or IP address, as detailed above. E-mail it to them or call them on the phone to let them know where you are today(Not where you want to go today, that's another "OS"). they can then:

 telnet FQDN  or  ftp IPa.ddr.ess.!!!

and all of a sudden they're in your den, or office or wherever you keep your computer. For more sophisticated methods of getting your address, read the "Dynamic IP hacks-HOWTO.

Just a Reminder: Read the whole Linux Gazette

This esteemed tabloid is just full of novice- to intermediate level tips and tricks.The Answer Guy, Two Cent Tips, and The Weekend Mechanic in particular, are good sources of the kinds of things that will make you a demi-guru in no time at all.

Formatting Floppy Disks in Linux

In DOS and Windows,formatting a floppy disk is a one shot affair which formats, erases data, and creates a file system on the floppy. In linux however, you have to format and create the filesystem in separate steps. At first glance, this seems backward, after all, isn't linux a more sophisticated OS? Why do things in two steps that the others do in one? The reason is that linux can read several filesystems so that data can be moved from one OS to the other. By mounting the floppy drive as MSDOS, VFAT, or other filesystem type the data can be read from the mount point in a manner that linux can make use of.

Other Stuff I've Collected/Found out Since Last Time

have trouble with the

 find

command?Try leaving your computer on overnight, and the next day use the

locate /filename |less

command instead. Locate is a database that is gathered during idle times on your computer Actually locate reads a database that is updated by a command in your system files, but if you give it time to breathe, usually overnight, it can locate any file on your hard drive(s). You can also try

 whereis filename

and you will get a location for the named file.

Next Time- Let me know what you would like to see in here and I'll try to oblige just e-mail [email protected] me and ask, otherwise I'll just write about what gave me trouble and how I got past it.

TTYL, Mike List