1 Get going with the system

Yes, that's all.

2 Files? What Files?

A byte is an integer, somewhere between 0 and 255. System interprets bytes as

• letters;
• pictures;
• program, that means a set of instructions to work on other files;
• or anything else you came to think of

2.1 File types

• *.txt = ascii text files.
  View with MORE or LESS.
  Edit with VI, VIM, JOE, AXE, XEDIT, MC, EMACS or an editor that you have written for your own.
  dos text files are usually not compatible with linux text files, because dos wastes 2 bytes for every line break instead of 1. There is a smart program called DUCONV that converts between the real and the want-to-be OS.
• *.tex = document file.
  It actually is a ascii text file with additional commands how to process the typed-in text. To be processed by TeX.
• *.dvi = output of tex. Can be
  • converted to PostScript by DVIPS or
  • directly sent to a dvi-capable printer or
  • viewed under X with XDVI.
• *.ps = document file, ready for print-out.
  It has all formatting and pictures in it, and does not contain a single trace of how you made it.
  Because it is text only, it consumes few disc space, and few time to be sent all over the world or just to a PostScript-capable printer.
  PC printers, who do not know PostScript, can print ps files by GHOSTSCRIPT.
• *.gif = picture, in CompuServe GraphicInterchangeFormat.
  Uses less disc space than uncompressed picture, but contains all data of original bitmap.
  Can be
  • viewed with ZGV.
  • viewed and processed with XV and XPAINT.
  • converted to *.jpg with CJPEG.
  • converted to *.eps with XV and then be inserted into a tex file.
• *.jpg = picture, in JapanesePictureGroup Format.
  Uses less disc space than gif file.
  Contains nearly all data of original bitmap - YOU control how much. The less you choose, the smaller is the file and the number of details.
  Can be
  • viewed with SEEJPEG.
  • viewed and processed with XV and XPAINT.
  • converted to *.gif with DJPEG.
  • converted to *.eps with XV and then be inserted into a tex file.
• *.eps = EncapsulatedPostScript.
  Contains graphic data (letters, pictures, tables, or alltogether, or more), to go into a ps file.
• *.pov = povray input file (see povray.htm).
• * = file without extension.
  maybe an executable. Executables (programs) tell the system how to process your files.
• .* = file with a dot as first letter.
  Usually configuration files. This way UN*X hides its files from been seen.
  You can see all hidden files in the current directory by LS -a.

3 Directories? What directories?

3.1 Welcome to the Linux file-tree.

/
|
|--bin
|
|--home
|  |
|  |--larry
|  |
|  |--susan
|     |
|     |--txt  diary.txt   impressions.on.vi.txt    to.do.list
|     |
|     |--tex
|     |
|     |--pictures
|
|--usr
|  |
|  |--bin
|  |
|  |--local
|     |
|     |--bin
|
|--tmp

3.2 Commands on files and directories

mousehouse:~$

You are in your home directory.

ls

shows all unhidden files in the current directory.

ls *

shows all unhidden files in the current directory.

ls a*

shows all files starting with a.
Examples: aaaaaaa.txt armstrong.tex a.a.a.a.a.pov

ls *a*.text

shows all files that have an A in their filename and end on .TEXT
Example: a.text bbbbabbbb.text aaaaaaaaa.text

ls -l

gives you a long list of all files.

             *xwrx-r--r is an executable, which may be
              |||         read, written and executed by the owner,
                 |||      read and executed by the owner's group,
                    |||   read only by the rest of the world.

vi newfile.txt

invokes vi and asks it

• to create newfile txt if it doesn't exist in the current directory;
• open newfile txt if it does exist in the current directory.

mv oldfilename newfilename

copies file oldfilename to newfilename, then deletes oldfilename.

rm deletefile

removes deletefile.
Please be careful! Any deleted file cannot be resuscitated! In NO way!

cd /home/susan/txt

Moves you in one of susan's directories.
If Susan does not want you to read her diary, most likely you have no permission to go into that directory. In the same way, you can protect your files from being read or changed or deleted by other users.

pwd

System tells you what directory you are in.

mkdir newdirectory

creates a new directory within the current directory.

cd upperdirectory

changes to upperdirectory.

cd ..

changes 1 directory down

cd ~

changes to your home directory.

cd /usr/local/lib

changes to /usr/local/lib, whereever you have been before.

mv /home/larry/newtext.txt /home/larry/txt/newtext.txt

moves ~/newfile.txt into ~/txt/newfile.txt.

cd ~
mv newtext.txt txt/newtext.txt

does the same as above.

4 Programs? What programs?

4.1 How do I invoke a program?

 programname [options] [inputfile] [> outputfile] 

• you must type the programname.
• If you have any options for the program, type them in.
  (The manual pages will tell you which options are available for which program.)
• if you want the program to read a file instead of reading from the keyboard, specify a inputfile.
• if you want the program to write to a file instead of writing to the screen, specify a outputfile.
  Do not omit the >. This is a piping command.

Please remember to switch OFF NUM LOCK. Else, BASH will behave unpredictable.

4.2 Which programs are available?

4.3 Which program suits my needs?

5 Customizing the system for your needs

Users cannot change or delete programs, for programs sit in directories that users may not write to.
Of course users may write programs and shells scripts of their own, and change them, and execute them, and share them with other users.

Most users want to change the defaults of some programs a little, e.g. have a blue-on-green desktop on the X Window system.
So the initialisation files of all programs are stored in ~ (your home directory) and hidden from the unexperienced user by starting the filename with a "." (period). ls -a shows all these files.

The existing programs have been set up by root to ensure that the according programs can be used at once, without any pending configuration work by unexperienced users.

Glance at them. Before changing ~/.anyrc, you should create .anyrc.backup.

I want to learn more about .profile.

I want to learn more about .fvwmrc.

6 Glossary

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