Hello Parham,

    Linux is a clone of the UNIX operating system.  If you can find a UNIX manual or book, that will help.  Linux is a layered operating system, much like the old Windows 3.11/MS-DOS operating system in the early 90's.  At the core, there is the kernal, and like a seed, it is surrounded by a shell.  The shell is your command line interface to the kernal and everything it does.  Surrounding that is the X11 graphical user interface, if installed.  X11 also contains a shell interface, usually presented in a virtual terminal window at X11 startup.  some shell commands you should know are:

cd = change directory.
ls list files/directories.
pwd = present working directory.
cat = catalog or display a file(s).
man = manual pages.
info = information pages.
alias = create keyboard shortcuts/macros.
chown = change ownership of a file/dir.
chmod = change file/dir modifiers for read/write/execute.
logout = log off your account.
reboot = reboot the computer.
halt = shutdown the computer.
passwd = change password.
su = switch to user.
more = pages a text file one page at a time.
less = like 'more' but better.
most = like 'less' but better.
grep = find text in a file.
find = find a file.
whereis = find a file.
locate = locate a file.
ed = edit a file.
vi = edit a file.
vim = edit a file.
mail = xmit mail.
pine = xmit email and news.
elm = like pine.
mutt = like pine.
tin = xmit news.
lynx = surf the web.
links = lynx with menus.
wget = download a website to disk.
tr = translate/change characters in a file.
sed = edit a data stream/file.

    A few good websitees for learning linux basics are www.slackware.com.  Find the "Slackbook" link and have at it.  The Linux Documentation Project is at www.ldp.org.  You can get questions answered at www.linuxquestions.org.  Another great place to find what's on your computer is in your /usr/doc directory.  Perform a:

cd /usr/doc
ls

to see what's installed and available.  Three maim directories where programs can be found are:

/bin
/usr/bin
/usr/bin/X11

System-wide configuration files are located in:

/etc

Personal configuration files are located in your home directory.  Enter the 'cd' command by itself to change to your home directory.

ls -a

lists all files in a directory, including hidden files that begin with a period.

/var

is where logs and other data is recorded.

/dev

is where devices are listed.  Everything, including hardware is listed here.  Other directories are:

/boot = where the kernal is.
/root = root's home directory.
/home = your user's home directories.
/sbin = system programs/daemons/services.
/opt = optional programs (commercial software).
/usr/local = your programs.
/usr/src = sourcecode directories.  Also:
/usr/local/src
/lib = system libraries.
/proc = kernal processes -careful!
/mnt = mount points for other hardware.

Other useful commands to explore:

tar, gzip, bzip2, groff, ping, traceroute, cut, echo, bash, sh, csh, ln, chfn, chsh, finger, telnet, emacs, startx...the list goes on and on, as there are over 4000 programs that can come in a Linux distribution, and that's not including the standard, bare-bones  linux commands.  Hope that helps, and welcome to Linux

          Michael