to get help in the command line (konsol, xterm) can type any of this:
~$ man <the-command-I-want-info-about>
~$ info <the-command-I-want-info-about> | less
the '| less' part is optional but will allowe you to scroll up and down.
or..
~$ <the-command-I-want-info-about> --help | less
and..
~$ help | less
Will give you a list of basic commands,
The simbols '~$' means the command line as regular user (as the 'C:\' in wondows)
If you see the simbols '~#' means the command line as root (root is the 'super user' or 'administrator')
There is no real meaning to extensions. All files are the same to the system, they are just files. (what makes them different is the permitions/setting of the file)
Storage devices (HD's, floppys, CD's) are mounted as folders.
so if you insert a floppy you need to do...
~$ mount /floppy
then to browse it just move to that directory...
~$ cd /floppy
~$ dir
If you can't mount floppys is because you have no permision by the admin (root)
to copy a file to a floppy...
~$ cp myfile /floppy
now... go explore !!!!!!!!!!!!