Hello all
I am trying to switch to linux, though it seems not so easy. at least as comfortable as with windows for day to day tasks regarding documents, pictures, sounds, videos etc.

first i want to get comfortable with commands. i see that general short guidelines found in many sections for configuration with command lines is not good enough for a newcomer.

I am looking for exhaustive excercises for checking various configurations to get to know the devices, command prompt better, without risking my system too much. (I installed Ubuntu on AMD Athelon 850MHz)

for example, just few lines over 'mount' command are not enough..

any clues?

Welcome to LQ!

There are manual pages for every command that can be read if you issue "man <command>" in a terminal. Here is a hands on guide that will help you get started, with some exercises: Introduction to Linux - A Hands on Guide

You don't need to touch the command line in Ubuntu... really...

If you are looking for a challenge, I suggest Slackware or Gentoo (especially gentoo...)

Here is what you need to know about simple linux command line:

nano, emacs, and VI are your command line editors. aplay, play, alsamixer are for multimedia. links, links2, and lynx are for internet use

mount [device] [/mount/point]
mkdir [directory]
cp [source] [destination]
cp -r [directory] [destination]
cp -r [sourcefolder/*] [destination/subfolder/]
mv [...] [...] (same options as cp)
rm -f -r [directory or file that just won't delete, use carefully]

/dev/hda = primary master
/dev/hdb = primary slave
/dev/hdc = CDROM usually, secondary master
/dev/hdd = secondary slave
/dev/sda = usually removable drive or SCSI drive
/dev/hda1 first partition
/dev/hda2 second partition
/dev/hda5 first extanded partition
/dev/hda6 second extanded partition

/proc useful place to look for info
cat /proc/cpuinfo (check for CPU info)
echo something
echo something > tofile
echo something >> toappendtofile
dd if=infile of=outfile

these are some basic commands, enjoy.