vi: Unix Text Editing

Transcription

1 vi: Unix Text Editing Windows & MacOS vi: Unix Text Editing v Pages

2 About IT Training & Education The University Information Technology Services (UITS) IT Training & Education program at Indiana University offers instructor-led computing workshops and self-study training resources to the Indiana University community and beyond. We deliver training to more than 30,000 participants annually across all Indiana University campuses. Our staff is comprised of enthusiastic professionals who enjoy developing and teaching computing workshops. We appreciate your feedback and use it to improve our workshops and expand our offerings. We have received several international awards for our materials and they are being used at universities across the country. Please keep your questions, comments and suggestions coming! In Bloomington, contact us at or call us at (812) In Indianapolis, contact us at or call us at (317) For the most up-to-date information about workshops and schedules, visit us at: Copyright The Trustees of Indiana University These materials are for personal use only and may not be copied or distributed. If you would like to use our materials for self-study or to teach others, please contact us at: IT Training & Education, 2711 East 10th Street, Bloomington, IN , phone: (812) All rights reserved. The names of software products referred to in these materials are claimed as trademarks of their respective companies or trademark holders.

3 Welcome and Introduction What You Should Already Know What You Will Learn What You Will Need to Use These Materials Getting Started Today s Project Introduction to vi Brief History It s a Screen Editor Creating a New File with vi Transferring the Exercise Files Opening a File to Edit with vi Setting Text Wrapping in vi Introduction to Modes in vi Command Mode Insert Mode Saving Files in vi Navigating Through a File in vi Simple Movement Commands (Left, Down, Up, Right) 11 Why the Funny Keystroke Commands? Multipliers Used with Movement Commands Jumping Ahead/Back by Word, Sentence, Paragraph.. 12 Jump to Beginning/End of Line Jumping to the File s End Jumping to a Particular Line Number Searching for Text String Creating and Editing Content Contents Entering Insert Mode Inserting Before/After Cursor Switching Back to Command Mode Inserting at the Beginning/End of Line Inserting on the Previous/Next Line Undo Deleting Text Deleting Single Characters Deleting Words Deleting Entire Lines Replacing and SubstitutingText Replacing a Single Character Substituting Several Characters Swapping Case Copy and Paste Yank Put Ex Commands Special Syntax Saving and Quitting a File Quitting a File Without Saving Showing/Hiding Line Numbers Insert (Read) Contents of Another File Search and Replace Globally Search and Replace Wrapping Up Contributions to These Materials Appendix: Some Useful vi Commands

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5 Welcome and Introduction Welcome to vi: Unix Text Editing. What You Should Already Know You should have already attended Unix: The Basics as well as XHTML: The Basics or have the equivalent skills. Specifically, you should be able to: manage files and directories in Unix upload files to a server set file permissions in Unix get Unix help create a Web page using XHTML structure your Web page for maximum efficiency and accessibility add presentation style to your page link to other Web pages What You Will Learn In this workshop, you will learn how to: start the vi program create new text files in vi open files for editing in vi navigate through file content in vi switch between command and insert mode issue commands in command mode insert, substitute, and replace text in insert mode delete text copy (yank) and paste (put) text search and replace text add (read) contents of second file to current file save files What You Will Need to Use These Materials To complete this workshop successfully, you will be provided with: a demo Unix account the use of vi on this demo Unix server the exercise files in the vi, folder: home.html, bridge_color.jpg, bridge_bak.jpg, dtd.txt, and styles.css vi: Unix Text Editing v

6 Getting Started Finding Help These materials presume you will begin work from the desktop, and have any required exercise files located in an epclass folder there. For instructions on obtaining the exercise files, see below. If you need assistance logging on or starting an application, please consult your instructor. If you have computer-related questions not answered in these materials, you can look for the answers in the UITS Knowledge Base, located at: Self-Study Training Want to learn more on your own? IT Training Online makes self-study computer-based courses available on a wide range of IT topics. You may also purchase STEPS workshop materials to use in learning on your own. To find out more, go to: Getting the Exercise Files Most of our workshops use exercise files, listed at the bottom of page 1 of the materials. In our computer-equipped classrooms, these files are located in the epclass folder, which should already be on the computer desktop. If you are using our materials in a different location, you may obtain the exercise files from our Web site at: Once you are logged on and have the needed files in an epclass folder on your desktop, you are ready to proceed with the rest of the workshop. 2 vi: Unix Text Editing v1.1.0

7 Today s Project The Unix operating system and variants continue to persist as preferred platforms in several arenas even though more recent operating systems have captured the lion-share of desktops. There is, in fact, a re-emergence of Unices as an alternative in many venues for many reasons. One area where Unix still has a sizeable audience is in Internet services, particularly for World Wide Web servers. Thus many system administrators, Web masters, and even content providers for Web resources need a working knowledge of the Unix operating system. Since nearly every aspect of working in a Unix environment involves dealing with text files, knowing how to create, manipulate, and modify text files is a critical skill. Today s project places you in the role of someone who has inherited responsibilities for maintaining an existing Web site. The home page of this site in particular has several errors and minor adjustments that need correcting, both to the text content as well as the styles applied to the document. While there are various ways to work with these documents on multiple platforms and then move them to a Unix server, it s often much more efficient to make small changes to files in the Unix environment where they reside. For this workshop you will be logging in to a Unix account which serves Web documents and you will use the vi text editor there to quickly and efficiently update these files. Introduction to vi The ability to modify files in a Unix environment is critical to many tasks at many different user levels, from system administration to simple Web page modifications. While each flavor of Unix may have it s own idiosyncrasies and different applications, almost all Unices have one text-editing package in common vi. Vi is not just limited to Unix platforms; versions have been created for VMS, Windows, and MacOS platforms to name a few. Due to this ubiquity, the vi editor is a handy tool for everyone needing to create or modify text files in a number of environments. It is a very flexible and powerful application, though not very intuitive or user-friendly. In particular, it s a very handy tool for making quick, small changes to documents on a Unix machine. Larger editing changes may be more efficiently accomplished with a number of other editing tools, so it s not always the best choice for creating new documents or making major revisions although some users become so familiar and enamored with vi s intricacies, speed and powerful flexibility that they will consistently use vi to the exclusion of most other editors. Additionally, some other text editing programs, like Pico, can insert vi: Unix Text Editing v

8 Brief History hidden and unnecessary control characters that may have an adverse effect on how text documents are processed. Comparatively, vi creates simple, clean, and reliable files. This workshop will introduce the basics of using vi to create, modify, and save text files in Unix. The name for this application, vi, is really intended to be an abbreviation of the term visual. As you ll quickly recognize, compared to many of the current text editing and word processing packages in use today, vi doesn t look all that much like a visual editor. Remember, however, that vi has been around for quite some time since This predates most graphical user interfaces. It s a Screen Editor Prior to vi, there were few options for editing an entire document. The editing tools of the time, like ed, were line editors and wouldn t allow users to scroll through entire multi-line documents or add more than one line of new text at a time. Vi was developed by a programmer working on one of the early versions of Unix (BSD) who became frustrated with the limitations and unfriendliness of these line editors. Additionally, this programmer, Bill Joy, wanted an editor that would work over very slow dial-up connections. The result is a flexible, powerful, compact, and highly responsive if not entirely intuitive editor. NOTE: This workshop uses a particular build of vi (actually vim) on a particular Unix build (actually Linux) available for members of the Indiana University community. Even though each Unix build and each version of vi may have it s own small idiosyncrasies, the commands and exercise steps in this workshop have been written to be generically applicable to as many environments as possible. With the appropriate exercise files, you should be able to complete this workshop with almost every standard build of vi. That is, in part, one of the reasons why vi is such a handy tool to have in your toolbox. If you find that this workshop does not work in any particular vi environment, we would very much like to hear about it ittraining@indiana.edu. Creating a New File with vi Even though it was built for the Unix environment, vi, and subsequent clones, run on most available operating systems. Some of these clones have a graphical interface that may include menus and other options which can be operated using a mouse. Most vi usage, however, is still based on keyboard input and launching the application from the command line. 4 vi: Unix Text Editing v1.1.0

9 This workshop will focus on this most basic operating premise. Therefore, to access vi and complete these exercises, connection to a Unix account will be necessary. To access the Unix account: 1. Open an ssh terminal client. 2. Connect to the appropriate server using the server address and login account detailed below: Server Address: mercury.uits.indiana.edu You will see a server message-of-the-day and command-line prompt ($). To start a new blank document with vi, simply type the vi command followed by a blank space and the name you want to give to the new file. 3. To see the files that already in this directory, type: ls 4. To begin the vi editor and create a new file, type: vi sample.txt This creates a blank file called sample.txt and puts the cursor at the very beginning of the file. NOTE: Depending on the length of the file, you may see tilde (~) characters on lines following the last line of a file. These are not part of the document and cannot be edited they re simply used by vi to fill the editor screen. Soon we ll look at the different modes in vi and how to move between them. For now, to start putting text in this file, you ll first need to tell vi you are ready to insert text. 5. To enter insert mode in vi, type: i Login: Password: You see the word INSERT appear at the bottom of the screen. Now vi is ready for keyboard input. vi: Unix Text Editing v

10 6. Type: Every good boy deserves fudge. The text should appear on the first line exactly as you ve typed it. But mistakes happen often in keyboarding, especially as you re learning a new application. If you make a mistake while creating text, vi will let you quickly undo errors. 7. To undo your last step in vi, type: u And if you ever are really unhappy with what you ve done, you can quit vi without saving your file. 8. To quit vi without saving the current file, type: :q! While this may seem cryptic at this point, these keystroke actions will be explained shortly. This action quits vi without saving any changes made since the last time the file was saved. Since we ve not yet saved this file, this effectively quits without creating our new file. 9. To list the files in our present working directory, type: ls You should not see sample.txt as a listed file here because, even though we asked vi to initially create this file, it was never saved. Transferring the Exercise Files Before we continue in today s workshop, we will need to transfer the exercise files into the demonstration account. 1. Open a file transfer window or application. 2. Locate the vi folder containing the workshop exercise files on your local machine. 3. Upload the vi folder into the www directory of your demonstration account using the file transfer application. Now that we have these files uploaded, we can examine the contents of these files using vi. Opening a File to Edit with vi Now we re ready to start editing existing files.. 6 vi: Unix Text Editing v1.1.0

11 1. Switch to the terminal client. 2. To move into the subdirectory of the www directory and start working on these new files, type: cd www/vi 3. To see a list of the files in this new directory, type: ls -al Now that the appropriate files are in place, we can open one in vi. Similar to creating a new blank document, initiating a file in vi from a Unix command prompt is as simple as typing the vi command followed by a space and then the name of the file to be opened. Since the home.html file is now a published Web document, we can also open it in a Web browser and see there the changes we make to the document in vi. 4. From the Unix command prompt, type: vi home.html 5. Open a Web browser application. 6. Navigate to the Web address, 7. Switch back to the vi document. The text file is now displayed and ready for your action. The easy part is over. The difficult part now is to determine how vi will allow you to make changes to your file. Setting Text Wrapping in vi Being a general purpose editor, vi may be used equally well for editing regular text documents or for files containing markup or programming code. You may instruct vi to automatically wrap lines of text when words get within a specified number of characters of the right margin.to do this, vi will insert new line characters into the file to force this wrapping. vi: Unix Text Editing v

12 You also may specify that no automatic wrapping should occur, which is typically preferred when editing configuration files or files containing code. Having new line characters inserted into such files could cause unwanted results or even syntax errors You can prevent this by telling vi to set the wrapping margin to be equal to zero. Since the exercise file contains XHTML markup code, let s make certain vi will not perform any unwanted wrapping. 1. To prevent automatic text wrapping from occurring, type: :set wm=0 This setting will be retained until you quit vi. Introduction to Modes in vi Command Mode The most important thing to realize when starting vi is that we can t start making changes or additions when we first open a file. There are two major modes in which vi operates - command mode and insert mode. To insert text we have to first tell vi to move into the appropriate mode. By default, vi opens in command mode. In this mode, vi is not expecting text input to modify the documents contents. This is very different from most other text editors. Instead, vi is expecting a command, initiated by keystrokes, to accomplish specific tasks such as navigating through the document, searching for text, saving a document, or entering into the mode for inserting text. Since, with most text-based versions of vi, there is no indicator to tell which mode vi is currently operating under, it s easy to become confused and enter a keystroke with effects other than intended. However, the Escape key is a valuable tool when the mode is not obvious. In insert mode, pressing the Escape key will take vi back to command mode. In command mode, the Escape key does nothing, though it may prompt a system error beep. So users can always press the Escape key to make sure they are in command mode. Let s give this a try. 8 vi: Unix Text Editing v1.1.0

13 1. To make sure you are in command mode, press: Insert Mode Depending on your system, you may have heard a beep. At the very least, you are now confident you are in command mode. As mentioned, in command mode vi is expecting keystrokes which will perform actions, rather than insert text into the document. These keystrokes are often the same keys used to insert text, but in command mode they are interpreted differently. We ll explore several of these command keystrokes, but for now let s experiment with this to demonstrate that many keys have different uses between the mode that inserts text and the command mode. 2. To move the cursor down one line, press: j You should notice that the mouse cursor moved down one line. In command mode, the j key instructs vi to move the cursor to the next line. The second mode in vi, then, is the insert mode. In this mode, when a keystroke is typed, that symbol is literally inserted into the document. There are many different commands that allow you to switch from command mode to insert mode, depending on exactly where you want to begin inserting new text. We ll also explore several of these insert commands, but for now let s get a quick example of switching to insert mode and entering text in a document. 1. To move the cursor onto the line <meta name="author" content="author name" />, type: jj The j key, again, moves the cursor down one line each time the j key is pressed. If you go too far the k key moves the cursor back up one line. Now to place the cursor so you can begin entering your name in the content attribute, you ll need to move the cursor to the right. vi: Unix Text Editing v

14 2. Press the l (lower-case L) key continuously until the cursor is directly over the lower-case a following content= NOTE: If you go too far and need to move the cursor back to the left, using the h key accomplishes this. We want to delete the phrase author name, which contains 11 characters including the space character. 3. To delete the string author name, type: 11x NOTE: This last command is the number eleven followed by a lower-case x. 4. Once your cursor is on the second double-quote following the content= text, type: i This puts the vi editor into insert mode at this cursor location. vi is now ready for you to begin entering text. 5. To insert your name in this location, type: your name Saving Files in vi You ll likely also notice after pressing the Escape key that the cursor jumps back one character space, a subtle indicator that you ve switched from insert mode back to command mode. Files, after being created or edited, need to be saved before they can be used by other applications. In vi, when a file is being edited, the permanent file itself is not being altered. Instead, vi creates a copy of the file in temporary space, sometimes called a buffer. Changes to a file are not committed to the permanent file copy until the file is saved. Vi refers to the save process as writing a file. The process used here to demonstrate the write command uses one of a unique set of commands which are covered in more detail later in this workshop. These commands begin by typing a : (colon) followed by additional command keystrokes. In particular, the write command is executed with the :w command. Now that we ve made some slight changes to the file, let s save it before moving on. Saving often minimizes the risk of losing work if something goes wrong, and using other options discussed later, it s possible to revert to a previously saved state if there is ever a need to get rid of all changes made after the last save. 10 vi: Unix Text Editing v1.1.0

15 1. To save this file and the last edits made, type: : Notice that this puts the cursor now on the bottom line of the window after a : (colon), indicating that vi is ready for a new command. 2. To write the file, type: w This writes the file, including any changes made in the buffer space, to a more permanent copy. Most versions of vi will, following a write command, then display in the bottom line of the window (called the status line or prompt line) the name of the file that has been written, possibly along with more file information such as the line and character count. Note as well that, after the write command, the cursor returns to the same location it was in before the write command was given. Navigating Through a File in vi The keystrokes used to navigate through a document in vi may seem a little odd at first, but with familiarity and practice, it becomes quickly apparent that they can be efficient and powerful. Simple Movement Commands (Left, Down, Up, Right) The most basic movement commands in command mode, moving the cursor one character space at a time, have already been introduced. To review: Left Down Up Right Cursor Movement h j k l Keystroke Why the Funny Keystroke Commands? It would be logical at this point to ask, Why not just use the arrow keys? Typically, you can. In most versions, the arrow keys on the keyboard work exactly the same, moving the cursor one character space at a time in the appropriate direction. For experienced vi users, however, these h-j-k-l movement keys on the keyboard are easier to reach while typing furiously. Also, some vi: Unix Text Editing v

16 earlier keyboards did not include the arrow keys, making the h-j-k-l movement keys necessary. Some operating systems may also map the arrow keys for special functions, making them unavailable for cursor movement. It would be very rare these days to find a keyboard without arrow keys or a system that does not make use of the arrow keys for navigation. Ultimately, which keys to use for simple navigation is a matter of user choice, but if the arrow keys do not work for whatever reason, while in command mode, the h-jk-l keys will. Multipliers Used with Movement Commands One of the extremely powerful features in vi is the ability to use a number with a command as a multiplying argument. This tells vi to execute that keystroke command as many times as the number suggests. Let s see a few examples of this, moving the cursor backwards and forwards using numeric arguments. If, for example, we need to move the cursor back 10 spaces, there s an easier way of accomplishing this than pressing the h key 10 times. 1. To move the cursor block, type: 10h The cursor block should have jumped back 10 spaces. Now if you need to move ahead in the document a certain number of lines, you can again use a numeric multiplier with the j key. 2. To move ahead 76 lines in the document, type: 76j This moves you 76 lines forward from your current line position. Notice as well that, even though you ve moved to a different line, the cursor should still be in the same relative position within that line. In other words, if your cursor was on the fifteenth character space in line 4, when you jump ahead 76 lines, your cursor is still on the fifteenth character space in line 80. Jumping Ahead/Back by Word, Sentence, Paragraph In addition to single character space movements, vi also recognizes strings in documents and can identify where a new word begins. It also tries to identify where a new sentence (following a recognized punctuation) begins and where a new paragraph (blank line) begins. Special keystrokes in command mode can be used to move the cursor forward or backward one word, one sentence, or one paragraph at a time. These commands also take a numeric multiplier 12 vi: Unix Text Editing v1.1.0

17 argument, making it possible to specify with a single command exactly how many words, sentences, or paragraphs forward or backward the cursor should be moved. The single keystrokes for these movements are: Cursor Movement Forward one word Backward one word Keystroke W (upper- or lower-case) B (upper- or lower-case) Forward one sentence ) Backward one sentence ( Forward one paragraph } Backward one paragraph { 1. Make sure your cursor is in the line that begins Off-the-Beaten- Path Travel is your full-service travel arranger 2. To move the cursor forward to the beginning of the next word, type: w Your cursor should now be at the beginning of the next word vi finds in the document. Note that the way in which vi defines a word may not always match your definition. For example, hyphenated words are treated as separate words, as are each of the hyphens used. 3. Now to move back three words, type: 3b Your cursor should be on the first character of the word three words before the word it was previously on. Note that, if your character is in the middle of a word, a single b command will move the cursor to the first character of that current word, not the word that comes before. 4. To move to the next sentence, type: ) Your cursor should be on the first character in the next sentence. vi: Unix Text Editing v

18 5. Now to move ahead two paragraphs, type: 2} Your cursor should be on the second blank line following the previous cursor position. Note that vi treats all these movement items (characters, words, sentences and paragraphs) as one long sequential string, so moving ahead 50 words at a time may put your cursor in a whole new paragraph it won t automatically stop at the end of your current paragraph. 6. To go back four sentence blocks, type: 4( The cursor is now located near the middle of the first paragrapgh. Jump to Beginning/End of Line On any given line, vi also provides single keystroke commands to jump to the first character space or the last character space on that line. These are, respectively, the 0 (zero) and the $ (dollar sign) keys. 1. To go back to the beginning of this current line, type: 0 (the zero key) Notice that the beginning of this line may actually be on the preceding line in the display. vi, especially in a Unix environment, regards lines as any strings of text separated by a return (more on the Return key and line ending characters later). When vi displays a line that is longer than the terminal window it is displayed in, the text will wrap to display on the next line, even though the two or more lines displayed are considered a single line. It also wraps the text precisely at the end of the display length (usually 80 characters) and does not attempt to keep words together in the display, like most current word processors. 2. To see where this line ends, type: $ This places the cursor on the very last character space in this line. Jumping to the File s End It s often handy to be able to go directly to the last line in a file. It s also handy to be able to jump to the beginning of a document. vi provides an easy keystroke command to quickly jump to the last line, the first line, or any specific line in between. 14 vi: Unix Text Editing v1.1.0

19 The specific keystroke for this Go To command is G (remember that case sensitivity is important lower-case g won t work.) By default, the G command will place the cursor in the first character position on the last line of the file. 1. To jump to the end of this file, type: G Now you see the cursor at the beginning of the last line in the document, and you may see tilde characters on several lines below the cursor. Jumping to a Particular Line Number The Go To command can also be used with a preceding numeric argument to specify the exact line number to go to. When executed, this will place the cursor on the very first character space for that identified line number. 1. To quickly jump to the very beginning of the document, type: 1G This places the cursor in the first character position for the entire document. Searching for Text String No text editor would be complete without a find option, and vi provides a handy utility for searching both forwards and backwards in a document for text strings. In command mode, searching forward for a chunk of text can be initiated with the / (slash) keystroke. Searching backward can be launched using the? (question-mark) keystroke. These are usually the same key on most keyboards, requiring holding down the Shift key to get the? keystroke. When using either of these searches, if a match is found, the cursor will be placed on the first character matching the text string searched for. 1. To try finding the first instance of the word your in this document, type: / When you start a search using this option, you ll notice that the cursor now jumps to the very last line in the terminal window, which now displays a / character. vi is waiting for you to type in the text you want to find. vi: Unix Text Editing v

20 2. To specify which character string to search for, type: your From the present cursor location in the document, vi will search forward through the document until it finds a match, placing the cursor at the beginning of that match. NOTE: Be aware that this is still case-sensitive, so only an exact match of what you type into a search operation will be returned. If an exact match is not found for a search, a Pattern not found error will be displayed and the cursor will not move from its original location. Also be aware that several special characters, like a period (.) cannot be included in a search without escaping these (specifically indicating to the vi command that you are including a special character in your string) with a preceding \ (backslash), e.g., visit\. Another helpful feature, searches can often be repeated to find the next match by using the appropriate / or? keystroke and then pressing [ENTER] without having to type the string in again. 3. To find the next instance of the string your in this document, type: / This places the cursor in the first position of the next match. NOTE: If a search does not find a match in the appropriate direction, it will wrap to either the beginning of the document (if searching forward using the / command) or the end of the document (if searching backward using the? command) and continue the search until the original cursor position is reached. Creating and Editing Content With the basics of navigation understood, it s possible to put the cursor in the correct location to enter insert mode. Entering Insert Mode Insert mode is, as the name suggests, the mode in which text is inserted into a document. Although there are numerous ways to switch into insert mode, and some additional ways of inserting text content, inserting text is the limitation of this mode. Nearly all other methods for working with the text in a document, such as deleting text, must be accomplished in another mode. 16 vi: Unix Text Editing v1.1.0

21 Entering insert mode from command mode is as simple as a single keystroke, much like many of the other commands covered so far. The options, however, are numerous, allowing the move from command to insert mode at several different cursor locations relative to the current cursor position. Inserting Before/After Cursor Typically in modern word processors the current cursor location is where users would expect text to show up when entered. Essentially, this inserts new text as typed and pushes the text following the cursor location to the right (at least in latin-based left-to-right text.) This is the same effect achieved in vi by entering insert mode with the basic insert command using the i keystroke. Wherever the cursor block is located, after using the i command, keystrokes will be interpreted as literal text being entered into the document. To begin entering a new word that will show up before the word found in the last search, you ll first need to enter insert mode. 1. To enter insert mode, type: i Some versions of vi may show an indicator that vi is now in insert mode, while others may show no difference at all. 2. To add a new word, type: all Once new text has been entered, you ll usually want to switch out of insert mode back to command. 3. To switch back to command mode, press: Some vi editors may show a display difference indicating a switch back to command mode, but most will at least move the cursor back one position when switching from insert mode to command mode. In some instances, you might want to start inserting text in the character space immediately after the cursor position. This is accomplished using the a keystroke from command mode. 1. To insert a new word immediately after the current space, type: a vi: Unix Text Editing v

22 2. Now that vi is again in insert mode and the cursor has been moved one position to the right, type: of This of course inserts the word of and pushes the text following this further down in the document. Switching Back to Command Mode While in insert mode, remember that keystrokes are treated as symbols to be inserted into the text. In command mode, these same keystrokes are interpreted differently, including the h-j-k-l and other keys used for navigation. Therefore, after inserting some text in a document, to move around the document once more it will usually be necessary to switch back to command mode. We ve demonstrated this technique already; switching back to command mode is done using the key. 1. To switch back to command mode, press: Inserting at the Beginning/End of Line At any given time, vi understands not only the exact cursor position within a document but also where the beginning and ending position of the line in which the cursor is located. Simple commands can also be used to place vi in insert mode in either the first character position or directly after the last character position in a line. The command keystrokes for these actions are very similar to the keystrokes for entering insert either at, or directly after, the current position, but they use capitalized keys the I command to enter insert mode at the beginning of the current line, and the A command to enter insert mode at the end of the current line. In this example, the first paragraph of the text section in this document is missing opening and closing paragraph tags. 1. To move to the cursor to the beginning of the current line and enter insert mode, type: I The cursor now jumps to the beginning of the current line. 2. To add the appropriate tag, type: <p> 18 vi: Unix Text Editing v1.1.0

23 3. Since this is the only addition needed here, switch back to command mode by pressing: 4. Now to add the appropriate tag at the end of this line, press: A This places the cursor in a new character position immediately following the last character in this line, ready for text input. 5. Type: </p> This completes turning this line into a well-formed paragraph element. 6. To switch back to command mode, press: Inserting on the Previous/Next Line vi can also quickly create a new line, either immediately before or immediately after the current line, ready for text to be inserted. Similar to the case sensitive way in which the i/i and a/a keystrokes are interpreted in command mode, adding a new line and switching to insert mode is done using a single keystroke the o command creates a new line in insert mode following the current line, while the O command creates a new line in insert mode preceding the current line. 1. To insert a new paragraph before the first paragraph of text in this document, press: O (Capital Letter O) This forces a new line before the current line and places vi in insert mode. 2. Type <p>please enjoy your visit.</p> 3. To switch back to command mode, press: Even though we ve switched from insert mode back into command mode, here the cursor does not jump back a space as it did previously. By pressing the [ENTER] key, we ve created a new line in this document. When exiting vi: Unix Text Editing v

24 insert mode and switching back to command mode, vi will try to move the cursor back a space but will not move from the beginning of a line to the previous line. We want to add a new paragraph following the next paragraph block. 4. To position the cursor two lines down, press: 2j This places the cursor in the blank space between two paragraphs. 5. Now to create the new line and enter insert mode, press: o (lower-case o) This adds a new blank line below and vi is now ready for new text input. 6. To add a new paragraph here, type: <p>and remember, your satisfaction is guaranteed.</p> 7. Once more, switch back to command mode by pressing Now we will save these changes, and view the results in the Web browser. 8. To save the changes to this document, type: :w This saves the file, so now the browser should display the updated version. 9. Switch to the Web browser. 10. Refresh/Reload this page in the browser window. The new paragraphs should display in the Web document now. 11. Switch back to the vi application window. Undo Mistakes are common in any text editing process, even more so when using an unfamiliar text editor. Knowing how to recover gracefully from errors then becomes a very useful and common action. In vi, the undo command (u) will remove the last command. This should not be confused with the last keystrokes. If text was added by switching into insert mode, then the command to enter insert mode, and all text inserted as part of that command, are considered the last command. 20 vi: Unix Text Editing v1.1.0

25 1. To get rid of the last block of text inserted, type: u Deleting Text The previous insert command, and the block of paragraph text inserted during that command, is undone, leaving your document as it was before that command was issued. NOTE: The amount of undo s available will vary from system to system. The original vi only allowed one undo. Immediately reissuing another undo command would, in fact, undo the undo replacing what had been undone in the first undo. In this way it was possible to toggle back and forth to alternatively see a document before and immediately after a command. Newer vi clones typically allow an extensive, often unlimited, undo history, allowing you to undo in reverse sequence virtually every action, even after saving a file. Command mode is the required mode for deleting text as described here. There are numerous options for deleting text, and much flexibility in using these options. Deleting Single Characters The most basic way to delete text is one character at a time. In order to delete a single character, the cursor block must be directly over that character space. The keystroke for deleting a single character is x. In the next paragraph in this document, the term scrunching is used. The preferred term is crunching so we ll want to delete the s from the beginning of this word. We could use the h-j-k-l keys to move to this spot, but it may often be more efficient to do a quick search. 1. To start a forward search, type: / This puts vi in forward search mode. 2. To identify the character string to search for, type: scrunch This finds that text string and puts the cursor on the first character in the string precisely the character we want to delete. vi: Unix Text Editing v

26 3. To delete this single character under the cursor, type: x (lower-case x) This deletes the letter s, leaving us with the desired term crunching. The single character delete command is similar to the different insert commands which started insert mode either at or immediately before or after a specific location based on the use of upper- or lower-case. As demonstrated, x deletes the current character space. The X command will delete the character space immediately before the current cursor location. Near the end of this paragraph, the term connect has an extra misspelled character at the beginning of the word. To get rid of this extra letter, we ll search for the correct term, and then delete the preceding character. 4. To again enter search mode, press: / 5. To search for the correct term, type: connect This search matches the term and places the cursor on the c at the beginning of this match. 6. To eliminate the errant character before the term connect, type: Deleting Words X (upper-case X) This deletes the incorrect character (the character before the string match), leaving us with the correctly spelled word. Deleting an entire word at a time is also relatively simple in vi. This, however, requires two keystrokes in command mode, an initial d keystroke indicating a delete action plus a w keystroke indicating to vi that the item to be deleted is the word beginning at the current cursor location. It s important here to realize that this means if the cursor is currently in the middle of a word, a dw command will not eliminate the entire word, but from the cursors location to the end of the word string. So in order to delete an entire word with dw, the cursor must be on the first letter in that word. Remember as well that most vi commands will also take a number argument as a multiplier. Therefore dw, and most other delete options, can be told to repeat a specific number of times. 22 vi: Unix Text Editing v1.1.0

27 Two words previously added in the first lengthy text paragraph seem unnecessary, and we d like to quickly delete these. First, we ll do a quick backwards search to put the cursor at the beginning of the first word. 1. To start a backward search, press:? This puts vi in a backwards search mode and will look for the text string you enter next. If the first term is rather generic, you may want to make the search more explicit by adding a second word. 2. To search for a match on two words, type: all of This searches backwards in the text until a match is found and places the cursor at the beginning of the match string. 3. To delete the next two words, type: 2dw This deletes these next two words from the document. Deleting Entire Lines Similar to dw, the command to delete an entire line is a two-keystroke command. The keystroke for this action is dd. Unlike dw, however, when the dd command is issued the entire line is deleted, regardless of where the cursor is located. Since vi does wrap text in the display and can have extremely long lines, it s often difficult to ascertain precisely where a line begins and ends. Therefore it may be necessary to use the movement keys (j, k, 0, $) to find line beginning and endings. The final paragraph before the footer section, <p>off-the-beaten-path Travel is a Limited Liability Company.</p>, can be eliminated, so we ll first do a quick search to jump to that line, then delete it. 1. To start another forward search, press: / 2. To find a unique text string from that line, type: Limited vi: Unix Text Editing v

28 3. Now that the cursor is on the first character in that match, type: dd This deletes the entire line. 4. To see the changes that you ve made so far as they would appear on the Web, type: :w This saves the file, so now the browser should display the updated version. 5. Switch to the Web browser. 6. Refresh/Reload this page in the browser window. These recent changes should display in the Web document now. 7. Switch back to the vi application window. Replacing and SubstitutingText Finding, deleting, and inserting text are the basics of text editing in vi. There are, though, some more efficient ways of replacing text items with new text. Replacing a Single Character The command to replace a character with another character is r. This puts vi into an insert overwrite mode just for one keystroke, then switches back to command mode. One example of the name of the company on this Web site has a single typographical error, an asterisk where there should be a hyphen. 1. To start the forward search process, press: / 2. To specify the character to be found, type: * This finds the offending character and places the cursor over that character location. 3. To replace this single character, type: r This puts vi in an overwrite insert mode on this character location. 24 vi: Unix Text Editing v1.1.0

29 4. To replace this character with a hyphen, type: - The character has been changed and vi is once more in command mode. Substituting Several Characters When a single character needs to be replaced with several new characters, the substitute command (s) is a better option. This command deletes the current cursor location and puts vi into insert mode. All keystrokes entered after the s command will be entered into the text document until the user switches back to command mode. In one of the XHTML paragraphs on this page, the text dance in meadows should rather say dancing in meadows. 1. To find this initial string, type: /dance This search find the matching word and places the cursor on the first letter. 2. To put the cursor on the letter e, type: 4l (lower-case letter L) 3. To delete the highlighted letter and switch into insert mode, type: s 4. Now to enter the appropriate word ending, type: ing Swapping Case The word ending now looks more accurate and vi is back in command mode. Often quick edits mean changing upper-case to lower-case or vice-versa for the same letter. vi provides a quick way of making these simple edits without deleting and re-entering the same letter in a different case. This is accomplished using the ~ (tilde) command. Near the bottom of this Web document is the term Quixotic. In this case, it should be spelled with a lower-case q. First we ll search for this string, then we ll use the ~ command to swap case for the first letter. 1. To search forward for the first few letters in the desired term, type: /Quix vi: Unix Text Editing v

30 2. Now that the string has been found and the letter Q is the current cursor location, type: ~ Copy and Paste This switches the Q to a lower-case q and leaves vi in command mode. Text editing often entails taking existing text from one location in a document and either reproducing or moving it to another location. One way of moving text to a different location is to delete it and then paste it into a new spot. It s also possible in vi to copy text without deleting it. When text is either deleted or copied, that text is placed in a temporary buffer. The contents of that buffer can then be pasted somewhere else. There are complicated ways of using multiple buffers in vi, but when text is deleted or copied using the simple options, that new text replaces whatever was previously in the buffer. Yank vi refers to the copy process as yanking text. Intuitively, then, the commands to yank text begin with a y. There is, however, no single y command. Instead, when yanking text, the user needs to specify exactly how much text is to be yanked. Several of the yank options include: Keystroke Yank Action Options Examples yw Yanks one word Can include a multiplier to specify how many words to yank yy Yanks one line Can include a multiplier to specify how many lines to yank y3w (yanks 3 words) 5yy (yanks 5 lines) 26 vi: Unix Text Editing v1.1.0

31 Keystroke Yank Action Options Examples y#movement Yanks begin at cursor location in the direction indicated by movement command multiplied by numeric argument Use to indicate how many characters and in which direction y7l (lowercase L) (yanks current character plus next 6 characters to the right) Let s experiment with just one of these yank options by copying a line including a CSS rule that we ll duplicate and then modify. 1. To find the style rule that specifies how list item bullets should be displayed inside the sidebar, type: /sidebar li 2. Now with the cursor on this line, to yank it to the buffer, type: yy 3. Now that this line has been copied, to move to the next blank line, type: Put j This puts the cursor on a blank line following the original line. vi refers to the paste process as putting text. Thus the command p is used to put copied text back into a document. The p command will put text from the buffer after the current cursor position. Alternately, the P command will put text from the buffer before the current cursor location. In the case where one or more lines have been yanked to the buffer, these commands will put the copied lines either before or after the current line respectively. 1. To put a copy of the yanked line below the current blank line, type: p This creates a new line containing the text from the line that was yanked. Now we need to make some modifications to this style rule. 2. Use the movement keys to place the cursor over the i at the end of sidebar li. 3. To enter insert mode after the cursor location, type: a vi: Unix Text Editing v