intro unix/linux 04

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intro unix/linux 04

  1. 1. Lesson 4-Mastering the Visual Editor
  2. 2. Overview <ul><li>Introducing the visual editor. </li></ul><ul><li>Working in an existing file with vi. </li></ul><ul><li>Understanding the visual editor. </li></ul><ul><li>Navigating through a file. </li></ul><ul><li>Adding text to a file. </li></ul><ul><li>Avoiding confusion while entering commands to shell and vi. </li></ul>
  3. 3. Overview <ul><li>Deleting text from a file. </li></ul><ul><li>Undoing editing commands. </li></ul><ul><li>Creating new files with the visual editor. </li></ul><ul><li>Making changes to the text. </li></ul><ul><li>Moving and copying text. </li></ul><ul><li>Writing a file and quitting the editor. </li></ul>
  4. 4. Introducing the Visual Editor <ul><li>Bill Joy, a student of the University of California, wrote the vi editor. </li></ul><ul><li>The UNIX/Linux visual editor is a powerful, fast, command-driven screen editor. </li></ul><ul><li>The vi visual editor is available on all systems and is an essential tool. </li></ul><ul><li>The vi editor allows the movement of cursor to a specific location in a file. </li></ul>
  5. 5. Introducing the Visual Editor <ul><li>The vi editor is present on every UNIX environment, uses few computing resources, and includes many tools. </li></ul><ul><li>Standard UNIX releases include vi, and Linux provides vim, which includes some vi improvements. </li></ul><ul><li>Command mode and append/insert are the two modes of the vi editor. </li></ul>
  6. 6. <ul><li>The command mode allows a user to access a file with basic vi commands. </li></ul><ul><li>The append/insert mode allows a user to insert data characters in a file. </li></ul>Introducing the Visual Editor
  7. 7. Working in an Existing File with vi <ul><li>Files are central to the UNIX computing environment. </li></ul><ul><li>The visual editor is used to create new files and edit existing files. </li></ul><ul><li>The vi editor does not permit text to be added directly when editing a file. </li></ul><ul><li>The “cat” utility can be used for creating a file in UNIX. </li></ul>
  8. 8. <ul><li>We can edit the files created by the cat command. </li></ul><ul><li>We can access/open the files by giving the &quot;vi filename&quot; command. </li></ul><ul><li>The command will open the files in the command mode. </li></ul>Working in an Existing File with vi
  9. 9. Understanding the Visual Editor <ul><li>Moving around in a file: </li></ul><ul><ul><li>Opening a file in vi allows a user to delete, move, copy and paste and save and quit the file. </li></ul></ul><ul><ul><li>A user cannot insert characters while in the command mode. </li></ul></ul><ul><ul><li>The fundamental way to move the cursor in a file is to do it with the direction keys. </li></ul></ul>
  10. 10. Understanding the Visual Editor <ul><li>Moving around in a file (continued): </li></ul><ul><ul><li>The vi editor interprets the h, j, k, and l keys as a command to the move the cursor in specific directions. </li></ul></ul><ul><ul><li>The workstation either flashes or beeps if an attempt is made to move the cursor beyond the existing text. </li></ul></ul>
  11. 11. Understanding the Visual Editor <ul><li>Moving around in the file (continued): </li></ul><ul><ul><li>The vi editor also provides a forward search command for moving the cursor to a specific word in the text. </li></ul></ul><ul><ul><li>The /text is the forward search command for moving the cursor to a specified text. </li></ul></ul><ul><ul><li>The “n” command can be used for locating the next occurrence of a target string specified in the forward search command. </li></ul></ul>
  12. 12. Understanding the Visual Editor <ul><li>Working with text: </li></ul><ul><ul><li>To insert characters to the file, we have to change from the command mode to the insert/append mode. </li></ul></ul><ul><ul><li>The vi editor provides the dd command for deleting an entire line of text from a file. </li></ul></ul><ul><ul><li>The “dd” command even deletes blank lines. </li></ul></ul>
  13. 13. Understanding the Visual Editor <ul><li>Working with text (continued): </li></ul><ul><ul><li>After dd finishes deleting, it remains in the command mode. </li></ul></ul><ul><ul><li>The “x” (x-out) command deletes only a single character under the cursor. </li></ul></ul><ul><ul><li>The “a” command switches the vi editor from the command mode to the append mode and allows text to be entered to a file. </li></ul></ul>
  14. 14. Understanding the Visual Editor <ul><li>Working with text (continued): </li></ul><ul><ul><li>The “u” command undoes the last text change made to the file. </li></ul></ul><ul><ul><li>The ESC key instructs the vi editor to switch from the append/insert mode to the command mode. </li></ul></ul><ul><ul><li>A user can check the mode he is working in with the ESC key. </li></ul></ul><ul><ul><li>The “o” command tells the editor to open a new blank line between the cursor line and the next line in the file. </li></ul></ul>
  15. 15. Understanding the Visual Editor <ul><li>Quitting the editor: </li></ul><ul><ul><li>The “wq” command instructs the editor to write the file and quit the editor. </li></ul></ul><ul><ul><li>The “q” command can be used for quitting the editor if no changes are made to the file being edited. </li></ul></ul><ul><ul><li>The “q!” command instructs the editor to quit without saving the changes made to the file. </li></ul></ul>
  16. 16. Understanding the Visual Editor <ul><li>Creating and reading a file in the editor: </li></ul><ul><ul><li>A new file can be created in the vi editor by specifying the filename with the vi command. </li></ul></ul><ul><ul><li>A file opens in the command mode. Text can be entered by switching to the insert/append mode. </li></ul></ul><ul><ul><li>The “r” or the “read” command locates a file and reads its contents into the current file, starting immediately after the cursor line. </li></ul></ul>
  17. 17. Navigating Through a File <ul><li>Using the direction keys: </li></ul><ul><ul><li>The arrow keys and the h, j, k, and l direction keys, either alone or in conjunction with the number keys, make it possible to move the cursor to any character in a file. </li></ul></ul><ul><ul><li>The “set number” command tells the editor to display the line number on the screen. </li></ul></ul><ul><ul><li>The commands “G” and “:$” instruct the editor to move to the last line of a file. </li></ul></ul>
  18. 18. Navigating Through a File <ul><li>Lowercase “n” or “/” (slash) can be used to instruct the vi editor to search forward, whereas uppercase N or ? (question mark) is used to search in the backward direction. </li></ul><ul><li>The “set ignorecase” command can be used to switch off the case-sensitivity feature of vi’s search mechanism. </li></ul><ul><li>The “set” command can be used to view the environmental features that are currently set. </li></ul>
  19. 19. Navigating Through a File <ul><li>The “w” command can be used to advance the cursor to the beginning of the next word. </li></ul><ul><li>The dollar sign ($) instructs the editor to move the cursor to the end of the current line. </li></ul><ul><li>The caret (^) and the zero (0) move the cursor to the beginning of a line. </li></ul>
  20. 20. Navigating Through a File Moving the Cursor in vi
  21. 21. Navigating Through a File Moving to a Specific Textual Character in vi
  22. 22. Navigating Through a File Moving the Cursor by Line Address and Location Display
  23. 23. Navigating Through a File <ul><li>Two single quotation marks instruct the editor to return to the previous location in a file. </li></ul><ul><li>The display adjustment commands are used to adjust the workstation’s screen display to move forward or backward to a different block or section of code, regardless of its context. </li></ul>
  24. 24. <ul><li>CTRL-F displays the next screen of a text file. </li></ul><ul><li>CTRL-D scrolls down one half screen of a text file. </li></ul><ul><li>CTRL-D scrolls up one half screen of a text file. </li></ul><ul><li>CTRL-B displays the previous screen of a text file. </li></ul>Navigating Through a File
  25. 25. Adding Text to a File <ul><li>The “i” (insert) command starts adding text to the left of the cursor. </li></ul><ul><li>The “a” and “i” commands instruct the editor to move from the command mode to the append mode and start adding text at the cursor position. </li></ul><ul><li>The “O” command is an instruction to open a line above the line where the cursor resides and shift to the append/insert mode. </li></ul>
  26. 26. Adding Text to a File <ul><li>The “I” command instructs the editor to move the cursor to the beginning of a line and to change to the append mode. </li></ul><ul><li>The “A” command moves the cursor to the end of a line and switches the editor to the append mode. </li></ul><ul><li>The I and A command instructs the editor to switch to command mode. </li></ul>
  27. 27. Avoiding Confusion While Entering Commands to Shell and vi <ul><li>The “who” command, when executed in a shell, lists the users currently logged on. </li></ul><ul><li>In the vi’s command mode, it moves the cursor to a specific position and moves over to the append mode. </li></ul><ul><li>In vi’s append mode, the characters are entered directly into the file being edited. </li></ul>
  28. 28. Deleting Text From a File <ul><li>Multiple lines, words, and characters can be deleted by prefacing the delete command with a number. </li></ul><ul><li>The uppercase “D” command instructs the editor to delete the remainder of the line starting from the character under the cursor. </li></ul><ul><li>The “df*” command deletes the text from the cursor to the first character * on the current line to the right of the cursor. </li></ul>
  29. 29. Deleting Text From a File <ul><li>The vi editor also allows lines to be deleted using the line number addresses. </li></ul><ul><li>The d command also allows a comma to be used for specifying a range of lines to be deleted. </li></ul><ul><li>Commands that employ line addresses require the ENTER key to be pressed after the command for execution. </li></ul>
  30. 30. Undoing Editing Commands <ul><li>The “u” command undoes the last editing change in the file. </li></ul><ul><li>The vi editor in Linux allows multiple changes to be undone. </li></ul><ul><li>The “U” command undoes any number of changes made to the current line where the cursor is located. </li></ul>
  31. 31. Creating New Files with the Visual Editor <ul><li>The vi filename command is used for creating a new file as well as editing an existing file. </li></ul><ul><li>The vi makes a buffer copy of a file if it exists, else it starts editing a memory buffer using the new filename. </li></ul><ul><li>A file created in vi can be made executable by executing the chmod command. </li></ul>
  32. 32. Making Changes to the Text <ul><li>The “r” command instructs the editor to replace the character located under the cursor with the very next character typed in by the user. </li></ul><ul><li>It can also be used for breaking up a long line into parts. </li></ul><ul><li>The uppercase “J” command can be used for joining two lines of text. </li></ul>
  33. 33. Making Changes to the Text <ul><li>The “R” command switches the editor to the “type-over” mode, wherein each letter typed replaces the character under the cursor as it moves down the line. </li></ul><ul><li>The “s” command substitutes the character under the cursor with the text typed in by the user until the ESC key is pressed. </li></ul><ul><li>The “cw” (change word) command allows a user to substitute a word or multitude of words for a single word. </li></ul>
  34. 34. Making Changes to the Text <ul><li>The “cc” command deletes the text from the current line and moves you from the command mode to the append mode. </li></ul><ul><li>The “C” command puts the editor into the append mode and allows a user to change part of the line from the cursor position to the end of the line. </li></ul><ul><li>The substitute command, a colon command, is used to exchange one regular expression for another in a file. </li></ul>
  35. 35. Making Changes to the Text <ul><li>The substitute command requires two words to be separated by slashes. </li></ul><ul><li>The “g” at the end of the substitute command is a flag and can be used for replacing all occurrences of the target pattern with the addressed lines. </li></ul><ul><li>The substitute command can also be restricted to lines having specific content. </li></ul>
  36. 36. Moving and Copying Text <ul><li>The “yy” command instructs the editor to copy the contents of the line where the cursor resides. </li></ul><ul><li>The “p” or “P” command is used for pasting a new line in a new location below the cursor line. </li></ul><ul><li>The dd and p commands can be combined to perform a cut and paste operation. </li></ul>
  37. 37. Moving and Copying Text Commands to Move and Copy Text
  38. 38. Moving and Copying Text <ul><li>Marking a place in the file: </li></ul><ul><ul><li>The “m*” command instructs the editor to mark a line of text and assign it a label specified in the *; it can have a value from a to z. </li></ul></ul><ul><ul><li>A single quote character with the label name can be used for moving on to a specific label. </li></ul></ul><ul><ul><li>Vi allows deleting, changing, and yanking of text from the current position to the marked spot. </li></ul></ul>
  39. 39. Moving and Copying Text The delete, change, and yank commands
  40. 40. Moving and Copying Text <ul><li>Marking a place in the file (continued): </li></ul><ul><ul><li>The mark command can also be used for simplifying the tasks of deleting, moving, and copying large blocks of text by marking both ends of the block. </li></ul></ul><ul><ul><li>Marking text is a powerful way to identify lines to delete, move, or copy. </li></ul></ul><ul><ul><li>The move or copy commands can be used for moving or copying a block of text specified using line numbers. </li></ul></ul>
  41. 41. Writing a File and Quitting the Editor <ul><li>The “w” command can be used for saving a copy of the current file to a new file. </li></ul><ul><li>The w or write command can also be used for writing a part or block of text from the current file to a new file. </li></ul>
  42. 42. <ul><li>The “w!” command instructs the editor to overwrite the contents of the file if it exists, else creates a new file for saving the contents of the current file. </li></ul><ul><li>The >> symbol, when specified with the w command, appends the text to the file specified. </li></ul>Writing a File and Quitting the Editor
  43. 43. Summary <ul><li>The vi is the editor used to create and edit files. </li></ul><ul><li>Vi provides several utilities to edit text. </li></ul><ul><li>Append/insert and command are the two modes of the vi editor. </li></ul><ul><li>Files created in the cat command can be opened in vi. </li></ul>
  44. 44. Summary <ul><li>A user cannot insert data without switching to the append/insert mode. </li></ul><ul><li>The I, a, i, A, o, and O commands instruct the editor to add text relative to the cursor position. </li></ul><ul><li>The vi editor provides the change (c), yank (y), and delete (d) operators for text operations. </li></ul>
  45. 45. Summary <ul><li>The vi provides various utilities to move, edit, delete, and replace text. </li></ul><ul><li>The :wq is used for saving and quitting the editor. </li></ul><ul><li>The vi editor facilitates global changes, where the user specifies the target for replacement and the replacement text. </li></ul><ul><li>Linux provides an advanced version of the vi, namely the vim editor. </li></ul>
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