Linux

Editor's Notes

• #3: If you are here you probably wonder about what is Linux and if it will be a good idea to switch to use Linux instead of Windows. Today class is an introductory class for Linux. Class following this one will be hands on Linux introduction.
• #16: Along the bottom of your screen is the panel , which contains many interesting features. Starting at the far left, there's that lovely red fedora, which is the icon for your main menu. Click it, an To the right of the main menu is a collection of icons, shown in Figure 3-2, that opens popular applications.
• #17: Evolution: A Microsoft Outlook-like program combining e-mail, calendar, task manager, address book, and more.
• #18: The layout location of these items can be customized, but the term used for each of them remains the same. The menu panel stretches across the top of the screen. It contains three menus and a number of default icons that start software applications. It also provides a clock, volume control applet, and a notification area. The desktop area is the screen space between the menu panel and the window list panel. The Computer, Home Directory, and Trash icons are located in the top left corner of this area. Those users more familiar with Microsoft Windows may equate these icons to the My Computer, My Documents, and Recycle Bin, respectively. The window list panel is located at the bottom of the screen. It features the Show Desktop icon, running applications as icons, and it gives access to the workplace switcher and the trash.
• #25: AbiWord – Word processor AddressBook Calendar Dia- linux Visio Emacs – text editor Gedit – like notepad Gnumeric - spreadsheet Nautilus – file manager Timetracking tool
• #27: Desktop Sawfish Window manager – controls the look and feel (you can change)
• #28: There are a variety of office type applications for GNU/Linux, but one of them stands alone. The defacto, full-featured, office suite is called OpenOffice.org. 'Openoffice.org' : word processor, spreadsheet, presentation and database application OpenOffice.org is completely compatible with many other office suites, including Microsoft Office.
• #32: There are many e-mail applications for GNU/Linux. However, one of the full-featured suites including a calendar, to do list and e-mail is Ximian Evolution. Ximian Evolution is a powerful and flexible personal information manager up to par with Outlook. Again, it's free, and the interface is designed to look similar to Outlook so the learning curve is low.
• #34: Most, if not all, distributions come with a Web browser installed and ready to use. Distributions that come with the KDE desktop environment generally come with Konqueror and distributions that come with the Gnome desktop environment generally come with Firefox. Konqueror is the central workhorse of the KDE desktop. Not only is it a Web browser, but it is also a file manager, an FTP client and a plethora of other things. Firefox is available for Windows, as well as GNU/Linux, so it's possible to try out the Windows version before switching over to GNU/Linux to ensure that it will be suitable for you. Oh, and they're all free as well. Other Web browsers you can try are Flock and Opera.
• #39: To open Terminal window right click on the desktop This grid of four boxes on the left represents four monitors. This really isn't four monitors; it's as if you had four different monitors connected to your computer. If you need more space to lay out files, or to segment your multimedia applications from your office applications while you're working, you can click in one of the empty boxes to access a completely fresh, uncluttered copy of your desktop along with a fresh panel. You can see which of your virtual desktops has open windows by looking in this box.
• #43: Root Directory ( / ) Top of the file system. Similar to in DOS /bin Contain the binary (executable code) of most essential Linux commands, e.g. bash, cat, cp, ln, ls, etc. /boot Contain all the files needed to boot the Linux system, including the binary of the Linux kernel. E.g., on Red Hat Linux 6.1, the kernel is in /boot/vmlinux-2.2.5-15 file /dev Contain the special files for devices, e.g. fd0, hd0, etc.
• #47: Standard way of interacting with linux. Will work with all version of Linux. X windows: GUI in linux. pwd – print working directory /home/perry (you see working directory) perry@nugget1 – what user you logged in as and what machine you logged into ls – list the contents of the directory cd – change directory cd.. - Moves you to the previous directory Tab on the keyboard will complete the command cp – copy UP arrow on your keyboard is the history command. It will allow you to go back to the previous command. clear – clears the screen. rm – remove file “– i” inquire to make sure we want to remove this file y or yes – it will do it mv – moves file from one name to the different one mkdir – make directory rmdir – to remove empty directory ls – F – to classify files in a directory ls – l – see more complete list of the directory’s contents ls – a – list all the files in a directory, including hidden ls – t – sorts by time ls – r – reverse the oldest files first Directory: / Executable program: * Hidden file: . Metacharacters: ? [] matches any on of the characters that are enclosed in the brackets With [] to indicate range of characters ^ (circumflex) (caret) used as the first character in the bracket, it matches any character not in the list. Ls b[^a,f]g display any file that begins with b and ends in g and where the second letter in the text string is neither an “a” nor an “f”. Grep “^on” * |* all the files in your home directory are searched for any occurrence of the letters “on” at the beginning of a line To move file content to another file: cat <fileneame> <filename> > <filename>
• #51: Emacs and Vi (Vim) have long been the two most popular editors on the Linux platform. You need some knowledge of how to use this editors, even if you will use more advanced GUI application software in Linux. This is because like Vi, the keyboard shortcuts are nothing at all like the ones people may be used to from Windows or a Linux GUI, where Ctrl-c copy's, Ctrl-v pastes and Ctrl-s saves.
• #52: To start you can open the terminal and type: emacs To exit: C-x, C-c This means hold down the Control(Ctrl) key, press x and then hold the Ctrl key and press c. You can hold down the Ctrl key through the entire operation or let go after C-x and treat C-c as a separate command — it makes no difference. Files To open a file in Emacs do C-x C-f. You will be prompted for the name of the file to open. Note that you will need to specify the exact name and path of the file for emacs to open it — no fancy Browse buttons here. If you specify a file name that doesn't exist, Emacs will create it in the current directory. Probably the easiest way to open a file is to specify it when starting Emacs. For example $emacs -nw myfile opens the file called myfile in the current folder. Again, if the file doesn't exist Emacs will create it. If you open a file and find the content has disappeared since you last looked at it, don't panic, you probably mistyped the name! NavigationAs with most other text editors you can navigate around a file using the arrow and page up / page down keys. However you should know that it is also possible to do this with Emacs command, which often provide much finer grained control and can save you a lot of key bashing to get around: C-f Move forward a character C-b Move backward a character   M-f Move forward a word M-b Move backward a word   M-a Move to beginning of sentence M-e Move to end of sentence   C-n Move to next line C-p Move to previous line C-a Move to beginning of line C-e Move to end of line Other important commandsTo save the file you are currently working on do C-x C-s.To undo your last move do C-x uAnother important command for beginners is C-g. Sometimes you may accidentally enter some command or emacs prompts you for something you don't understand or want to know about emacs will just drop whatever it was asking you about or doing and let you get on with it. To delete a word do M-d and to delete a line do C-k. Both of these commands can save a lot of key bashing. They will however only delete text to the right of the cursor. SummaryKnowing how to find your way around Emacs can save you a lot of grief when trouble strikes and its definitely worth it to use emacs for a while even if other easier to use editors are available. When just starting with emacs it can be a good idea to keep a short list of essential commands handy until you know them off:C-x C-c Exit Emacs C-x C-f Open a file C-x C-s Save the file C-x u Undo   C-g Cancel command/get rid of prompt M-d Delete word C-k Delete line   C-f Move forward a character C-b Move backward a character M-f Move forward a word M-b Move backward a word M-a Move to beginning of sentence M-e Move to end of sentence C-n Move to next line C-p Move to previous line C-a Move to beginning of line C-e Move to end of line
• #53: From the command line, type vi blah The editor will appear on-screen, with a tilde, ~, on evey line, and at the bottom of the screen it says "blah" [new file]. If you want to put anything into this file, you have to put vi into insert mode. Do this by typing the letter 'i' on its own. "-- INSERT --" appears on the bottom of the screen. Now you can type in anything you want. Try typing "Hello", and then on a new line "World". Now try going back up to the line above, using the cursor keys and try to delete Hello. You wont be able to. When you give a Carraige Return (Press Enter in other words), the text on that line becomes static. If you want to delete it, heres how. Press your Esc button on the top left of the keyboard, and the "-- INSERT --" at the base dissapears. Vi is ready to accept a new command. The only thing here is that vi will only delete what is in front of the cursor, let me show you. Bring the cursor to the start of Hello, and press the x key once. Now only 'ello' remains. This doesnt really make any sense, so we'll delete the line altogether. Press 'd' twice in quick sucession. Now we have the word 'World' on its own. Press 'i' and insert "Hello" again. This time, leave the text in insert mode. Press the "Insert" key on your keyboard, its above the cursor keys. The "-- INSERT --" at the base of the screen has been replaced with "-- REPLACE --". Now type the word "Nurse" over the existing "World". Press Esc again to return to the ready mode. Vi has a search tool too, which I find indispensable. From the ready mode, type in a slash, /, and input the text you want to look for. Remember, since Linux is case sensitive, looking for "money" is not the same as looking for "Money". Well, what about saving the file, or quitting without saving? What about just quitting? Its easy. From the ready mode, type in ":w" to write the file ... you already supplied the file name when you typed 'vi blah' earlier. The editor will return this on the status line : "blah" [New File] 1 line, 12 characters written. Lets quit out of it altogether. Type in ":q“or :quit!. You have been returned to the command prompt. There was an easier way of doing that ... from the ready mode in the editor, you could have just typed in, in cap:itals, "ZZ" ... this saves the file and quits. If you had wanted to quit without saving the changes, you could have just typed in ":q!", and nothing would have saved ... blah wouldn't have existed.
• #54: Smaller program, more primitivy. There are 3 modes: Command mode X mode Edit mode go into insert mode (by either pressing the letter 'i' or the insert key) delete text to the right of the cursor one character at a time with 'x' delete text one line at a time by pressing 'd' twice in quick succession search for text with '/' save text to a file (:w) and exit vi (:q or :q! if you don't mind losing changes). “Exc” key will take you to the command mode. I – Insert Esc Shift “:” and “wq” – write my changes and quit “dd” delete line of text “cat” prints file to the screen Say that again.You can have a command repeated a number of times by first typing in the amount of times that you want the command to occur so to delete a seven lettered word just type '7x'.You might wonder about the above line 'delete text to the right of the cursor' - is this excess pedantry or is it leading on to something useful?The latter applies; pressing 'X' deletes the character immediately to the left of the cursor and typing 7X, for example, deletes any seven characters that are immediately to the left of the cursor. So what happens if you are at the end of a 21 character line and you type '30X' - do nine charaters of the preceding line get deleted?No, the above line will remain intact but any the text to the left of the cursor will indeed get deleted. You can, if you want to, repeat a command just once; by pressing '.', this I suppose could be called the 'redo' button; it has a counterpart ('u') which will undo the last change. There's more than one way...to delete a word.Now, just to get back to deleting words. I mentioned that you could use '7x' to delete a seven lettered word. That's all well and good if you don't mind counting off the number of letters in whatever word it is that you want to delete. There's a better way to do this (there's always a better way).You can delete words with 'dw' and 'db'; use 'dw' for deleting words to the right of the cursor and 'db' for deleting words to the left - and if you want to delete seven words then use '7dw'. Moving the cursor.This moves on (hur, hur) rather nicely to the next thing that I want to get to - moving the cursor around. Obviously you can use the cursor keys but there are other ways of doing it.For example, if you want to move to the start of the previous sentence use '(', if you want to move on to the next one then press ')'. You can go squiggly if you want to move around one paragraph at a time and use '{' or '}' respectively. If you only want move around by a few words then use 'W' and 'B'.The great thing about all of this is precision. And I haven't even gotten to the good stuff yet. Cut & Paste.Do you remember about 'dd', and that it deletes lines one at a time? Well here's something nifty that you can do with it and just one other command. Let's say that you have a four line block of text that you want to move (be it source code or whatever). Move the cursor to the first line of that block of text and type '4d', then move the cursor to where you want to put the text and type 'p'. This will put the text you previously deleted back in, after the cursor. Using 'P' will insert the deleted text before the cursor. Copy & Paste.So now you know how to cut and paste text in vi.The next thing to learn is how to copy and paste text and there really isn't anything to it at all; instead of putting text into the memory buffer by deleting it text needs to be put there without deleting it. This is done by yanking the text.If you want to yank four lines of text into the buffer, move the cursor to the first line of that block of text and type '4Y'. You can then use 'p' or 'P' to place a copy of that text elsewhere. Other ways to change text.There are a few other ways that you can use to edit text. If, for example, you have typed in 'ilug' where you meant 'ILUG' you can either press 'R' with the cursor at the start of 'ilug', type the abbreviation in with caps lock on and press ESC to get out of replace mode. Or you can do it quickly by positioning the cursor and then typing '4~'. And if you want to delete to the end of a line 'D' will work just fine. Windows.Sometimes it can be quite handy to have more than one file open in vi at the same time - specifications in one 'window' and the source code in another for example.To do this you need to have one file open first and then press Ctrl & w (the control and 'w' keys at the same time) followed by 'n'. This will result in a new window created at the top of the screen, with the screen divided equally between the two windows.To edit a file in this new window you need to type ':e' followed by the name of the file. You can keep on doing this until you have as many files open as is needed. Moving between the windows is fairly simple. Press Ctrl & w first to let vi know that you want to do something about the windows and then press: t if you want to move to the top one b if you want to move to the bottom window Up arrow or down arrow to move to a window in the middle, you can also use 'j' or 'k' if you don't have any arrow keys for some reason. Typing ':q' will close the window that the cursor is in, if you want to close all other windows then press 'Ctrl & w' followed by 'o'.
• #55: You'd be amazed how many people make this complaint. They come to Linux, expecting to find essentially a free, open-source version of Windows. Quite often, this is what they've been told to expect by over-zealous Linux users. However, it's a paradoxical hope. As a simple example, consider driver upgrades: one typically upgrades a hardware driver on Windows by going to the manufacturer's website and downloading the new driver; whereas in Linux you upgrade the kernel. This means that a single Linux download & upgrade will give you the newest drivers available for your machine, whereas in Windows you would have to surf to multiple sites and download all the upgrades individually. It's a very different process, but it's certainly not a bad one. But many people complain because it's not what they're used to. But switching from Windows to Linux is like switching from a car to a motorbike. They may both be OSes/road vehicles. They may both use the same hardware/roads. They may both provide an environment for you to run applications/transport you from A to B. But they use fundamentally different approaches to do so. Windows/cars are not safe from viruses/theft unless you install an antivirus/lock the doors. Linux/motorbikes don't have viruses/doors, so are perfectly safe without you having to install an antivirus/lock any doors. Linux users are in more of a community. They don't have to buy the software, they don't have to pay for technical support. They download software for free & use Instant Messaging and web-based forums to get help. They deal with people, not corporations.
• #56: Hardware independent network base windows set. It is not GUI by itself, but GUI can be build on top of it