Linux: A Quick Guide

This guide is meant for experienced unix users, but are new to linux, or find a linux box and need to get going quickly. Very practical, with some buzzwords so you know what to do. I will not discuss installation, I assume somebody has already done that for you.

Basics

Linux is a very complete installation of unix. It probably 'feels' more like SunOS then Solaris, but has a BSD features as well as SYSV features. POSIX compliant, they say. You will probably find the GNU utilities (ls, mv, cp, find, grep, awk, make, ...) for all the commands you would use on a daily basis.

Booting

If you still have to boot your PC, there are several possibilities, of which I list the following common ones:

with a boot floppy. It is probably labeled and you simply boot all the way to a "login:" prompt.
LILO (LInux LOader). This is a bootstrap method (technically it has a little bootstrap loader on the master boot record of you boot drive) which allows you to choose your boot. Most often it's configured such that it waits for a few seconds at the "boot:" prompt, which you may have to activate with the CTRL or SHIFT key. At the prompt you can then enter the boot mode. Hit the TAB key to see which the valid options are.
LOADLIN from DOS, which assumes you are already in DOS. There should be a batch file called LINUX.BAT, just execute it. It might live in C:\LODLIN, or in one of the elements of %PATH.

Consoles

The bare login you will find on your linux box is often referred to as the console (tty1). In fact, most linux kernels are configured with a number (default: 6) virtual consoles (VCs, tty1 through tty6). Each provides you with a login shell, and you can switch between VSs using the infamous function keys: ALT-Fn (n=1..6). You can cut and paste with the mouse, if the gpm program is running. Selection is done with the left mouse button (and drag it over the section you want to cut), and paste it with the right mouse (the middle mouse button is not used in this context). Common shells are sh (actually: bash) and csh (actually: tcsh).

X-windows

You can start X-windows with startx, which is actually a script that calls xinit with optional arguments (such as the ones where you select 8bit or 16bit colors). The most popular window manager is probably fvwm, controlled by a .fvwmrc file, but both twm and openwindows are available. You will find most, if not all, of your favorite X-windows features in what will appear on your screen with the following unique features:

you can shut down X-windows quickly with CTRL_ALT_BACKSP (don't confuse it with CTRL_ALT_DEL; this will shut down linux and reboot the machine)
you can cycle through different window configurations with CTRL_ALT_+ (forwards) and CTRL_ALT_- (backwards)
when the physical screensize is smaller than the virtual screensize, moving your mouse to the edge will cause the display to scroll correspondingly.
If you have a mouse with two buttons, the middle mouse is emulated by hitting both the left and right mouse button at the same time.

Caldera

caldera is a commercial version of linux. It's most visible aspect is the window manager, which has drop-and-drag and has a lot of the Windows96 look and feel.

Devices

Here are some common deviced (see also /dev/MAKEDEV), with their DOS counterpart, and for some an often used nickname (symlink).

     /dev/fd0        A: floppy                                      /a
     /dev/fd1        B: floppy                                      /b

     /dev/hda1       C: first partition on the first IDE drive
     /dev/hdb2       second partition on the second IDE drive
     /dev/sda1       first partition on the first SCSI drive

     /dev/scd0       first SCSI cdrom                              /dev/cdrom
     /dev/rmt0       first SCSI tape                               /dev/tape

     /dev/ttyS0      COM1:                                         /dev/mouse
     /dev/ttyS1      COM2:                                         /dev/mouse

     /dev/cua0       COM1:                                         /dev/modem
     /dev/cua1       COM2:                                         /dev/modem

     /dev/lp0        LPT1:                                         /dev/printer

DOS/WINDOWS

Depending on how your system manager (you?) has setup your removable media (floppy, cdrom etc.) in the /etc/fstab file, you may be able mount and unmount a DOS floppy with commands like
```
    mount -t msdos /dev/fd0 /mnt
    umount /mnt
```
but the mtools package is often much easier to use. E.g.
```
    mdir a:
    mcopy file a:
    mcopy a:file .
    mdel a:file
    mtype a:file
    mformat a:
```
If your system also has a DOS partition, it's often mounted at bootup. It could be in /DOS (check /etc/fstab). You can transparently copy files from and to this /DOS tree, but remember the conversion of textfiles between DOS and unix (on linux use todos and fromdos).
There is also a Windows emulator (wine), but it's very much still in development. A number of applications appear to work however.
There is also a MacIntosh emulator, executor, which also allows you to read and write MAC floppies.

There exists a rather well functioning DOS emulator (DOSEMU), that can be activated with dos in a console , and xdos. You may have to umount your DOS partition if you need write access. Use exitemu to exit.

Communications

Popular modem communication programs are minicom (a procom lookalike) and seyon (an X-windows program). Setting up a PPP or SLIP link is mostly done via a simple script (e.g. pppstart and pppkill). Alternative networking is done with the term or slirp package that emulate a TCP/IP connection.

Printing

Often printers are configured for DOS, and if you try and use lpr you will get the whole file on one line, or get the infamous staircase effect. You can try filtering your unix textfile through todos:

    todos < file | lpr

Printing postscript files is done via a script that uses ghostscript to converts postscript to your printers native format. See /etc/printcap.

SHUTDOWN/REBOOT

You cannot simply turn the power off. You can either run shutdown or reboot, and then turn off the power when told it's safe.

Peter Teuben; 7-feb-96