CSC 414 Tutorial, Spring 2003

Nouhad J. Rizk Operating system 1/14 Workshop: Using the vi editor References • Learning the vi Editor, by Linda Lamb. O'Reilly and Associates, Inc. • vi man page Why learn vi? • It's installed on nearly all UNIX systems • It works in VTxx mode, in case you don't have X-Windows • It's a screen editor, not a line editor, so it's better than editors such as ed or ex Other editors Editor ASCII or X Windows Full-screen or line editor Lexical parsing? emacs either full-screen yes lpex X Windows only full-screen yes dtpad X Windows only full-screen no vi ASCII only full-screen no ined ASCII only full-screen no ed ASCII only line editor no ex ASCII only line editor no Notes: • ASCII refers to text only. • X Windows refers to a graphical mode, reminiscent of MS Windows. • ASCII editors such as vi can still be used under X Windows by opening a psuedo- terminal such as xterm or aixterm; however they do not directly support the graphical features of X Windows. • Lexical parsing refers to the ability of some editors to recognize and highlight keywords in computer languages such as Fortran or C. Overview of vi vi modes • Two modes: Command mode, and input mode • Command mode is the default Nouhad J. Rizk Operating system 2/14 • In command mode, anything typed is interpreted as commands • To go to input mode, hit the letter i • Once in input mode, everything you type is interpreted as text • To return to command mode, hit the ESC key vi commands • Case sensitive • Usually one or two characters • vi commands generally don't require hitting the ENTER or RETURN key • ex commands begin with colon (:) and require hitting the ENTER or RETURN key. ex is a line editor which underlies vi; vi is visual mode for ex. Getting in and out of vi • To edit a file, enter the vi command from the UNIX command prompt: • vi filename • Once in vi, you are automatically placed in command mode • To go to input mode, hit letter i • Begin typing text • Return to command mode by hitting the ESC key • To save the file, enter :w • To quit the file, enter :q • To save and quit, enter :wq • To quit without saving, enter :q! Moving around Moving one character at a time Function Key sequence Move up one line Letter k, or up arrow key Move down one line Letter j or down arrow key Move left one character at a time letter h or left arrow key Move right one character at a time letter l or left arrow key Scrolling Nouhad J. Rizk Operating system 3/14 Function Key sequence Scroll up one line letter l or up arrow key Scroll down one line letter j or down arrow key Scroll forward one screen ctrl-f Scroll backward one screen ctrl-b Scroll down half screen ctrl-d Scroll up half screen ctrl-u Global movements Function Key sequence Go to a line, by line number nG or :n (where n is a line number) Go to the bottom of a file G Go to top of file 1G or :1 Display line numbers :set nu Suppress line numbers :set nonu Moving within a line Function Key sequence Move right one character letter l, or right arrow key Move left one character letter h, or left arrow key Move to the beginning of a line 0 (zero) Move to the end of a line $ (dollar sign) Moving by words Function Key sequence Move to the next word (treating punctuation as separate words) letter w (lower case) Move to the next word (treating punctuation as part of the word) letter W (upper case) Move to the previous word (treating punctuation as separate words) letter b (lower case) Move to the previous word (treating punctuation as part of the word) letter B (upper case) Nouhad J. Rizk Operating system 4/14 Moving by paragraph Move to the next paragraph } (right curly bracket) Move to the previous paragraph { (left curly bracket) Locating text Function Key sequence Find a string Slash key (/) followed by string Find next occurrence Letter n Search backward for a string Question mark (?) followed by string Search backward for previous string Question mark (?) and enter key Editing commands Function Key sequence Insert letter i Append letter a Delete letter d (upper-case D will delete to the end of a line) Move delete (letter d) followed by put (letter p) Copy yank (letter y) followed by put (letter p) Adding text Function Key sequence Go into input mode letter i Go into append mode letter a Add a line and go into input mode letter o Return to command mode ESC key Deleting text Note: You must be in command mode to use the following commands. Function Key sequence Nouhad J. Rizk Operating system 5/14 Delete a line dd Delete n lines ndd (where n is the number of lines to delete, e.g. 2dd) Delete a single character letter x Delete to the end of a line letter D (upper case) Delete a word dw Delete up to some string d/string/ Copying text Function Key sequence Get text into buffer (yank) letter y Put text from buffer onto screen (put) letter p Get a line into buffer yy Get n lines into buffer nyy (where n is a number, e.g. 3yy) Get all text from current cursor location, up to but not including some string y/string Get all text from cursor to bottom of file yG Moving text Moving text is done by first deleting it (d), then putting it (p). Please refer to the section above on deleting text. Joining and splitting lines Function Key sequence Join the next line to the current line letter J (upper case) Join the next n lines nJ (where n is the number of lines) Split a line Hit letter i at location to split, then hit the enter key More ways to add and replace text Note: All the following commands (except r) leave you in input mode. Remember to hit the ESC key if you want to return to command mode. Insert text at current cursor location letter i Nouhad J. Rizk Operating system 6/14 Insert text at beginning of line letter I (upper case) Append text after current cursor location letter a Append to end of current line letter A (upper case) Open new line below cursor letter o Open new line above cursor letter O (upper case) Substitute a single character at cursor letter s Substitute entire line at cursor letter S (upper case) Replace a single character (but don't go into input mode) letter r Replace current text letter R (upper case) Global replacements Function Key sequence Substitute first occurrence of a string on the current line :s/old/new/ Substitute all occurrence of a string on the current line :s/old/new/g Substitute all occurrence of a string within a range of lines :nn,mms/old/new/g (where nn,mm is a range of line numbers separated by comma) Substitute all occurrence of a string within a file :1,$s/old/new/g (where 1,$ indicates the range of line numbers from line 1 to the end of file) Same as previous (replace all occurrences in a file) :%s/old/new/g (where % is an abbreviation for 1,$) Global replacement, confirm substitutions :%s/old/new/gc (You will be prompted as to whether to perform each substitution. Enter y to confirm, or just hit enter to bypass) Repeating and undoing edits Function Key sequence Repeat period (.) Undo last change letter u Undo all changes on current line letter U (upper case) Edits across files Nouhad J. Rizk Operating system 7/14 Reading and saving into other files Function Key sequence Read another file into current file at cursor location :r filename Read another file into current file, place it after some line number :nnr filename (where nn is a line number; $ is end of file) Write text from current file to a new file :w newfile Overwrite an existing file with the contents of the current file :w! some.file Use % (current filename) to create a new file :w %.new Append text from current file to another existent file :w >> newfile Write a range of lines from current file to another file :nn,mmw newfile (where nn,mm is a range of lines; $ means end of file) Editing multiple files To edit another file while editing a file, use :e :e filename Then use :e # to switch to the alternate file: :e # You can also specify two filename on the vi command: vi file1 file2 Initially you are placed in an edit session for the first file. To edit the second file in the sequence, use: :n To go back to the alternate (first) file, use: :e # Using named buffers • vi provides up to 26 named buffers (a-z) • You can store text from an edit command into a named buffer to be retrieved later. Precede an edit command with double quote and a buffer name. • Example: Yank a line into a named buffer, buffer b: • "byy Nouhad J. Rizk Operating system 8/14 • Once the buffer has data stored into it, it can be retrieved using the put (p) command. Example: • "bp • Copying is done by a sequence of yank and put; move is done by a sequence of delete and put. • Delete a line and store it into buffer b: • "bdd You can then move your cursor, and use "bp to move the text to the new location. • Named buffers are stored across edit sessions. You can use the :e command to edit a second file while still inside the first. The use p to retrieve named buffers. • % and # refer to the current and alternate filenames. To switch from to the other file, enter: • :e # Tailoring vi Set commands Function Key sequence Abbreviation Turn off Ignore case during a search :set ignorecase :set ic :set noic Display line numbers :set number :set nu :set nonumber Report changes larger than n lines (default is 5) :set report=n none none Show current mode (input, replace modes) :set showmode none :set noshowmode Searches will wrap around the end of file :set wrapscan :set ws :set nows Note: In general, you can always turn off an option by preceding it with no. Creating a vi profile • vi reads .exrc from your home directory as it's profile • set commands in the .exrc file should not include the colon Nouhad J. Rizk Operating system 9/14 Summary of most useful commands Function Key sequence Save current file :w Save and quit :wq Quit without saving latest changes :q! Go into input mode i Return to command mode ESC key Add a line and go into input mode o Go into replace mode R Replace a single character r Delete a single character x Delete a line dd Delete n lines ndd (e.g. 3dd, 5dd) Delete to end of current line D Delete to end of file dG Go to top of file :1 Go to botton of file G Scroll forward one screen ctrl-f Scroll backward one screen ctrl-b Copy a line yy followed by p Copy n lines nyy followed by p Copy up to but not including some string y/string followed by p Global change :%s/oldstring/newstring/g Show modes :set showmode Show line numbers :set number (turn off with :set nonu) Exercises Please note: Within vi, ex commands, or commands starting with a colon (:) require that you hit the return key to enter them. Other commands not starting with colon (:) don't require the return key. Basic editing 1. Edit the file from the previous workshop: Nouhad J. Rizk Operating system 10/14 2. vi test.file 3. Go to the bottom of the file: 4. G 5. Pull the last line into an unnamed buffer: 6. yy 7. Place the buffer contents after the current line (the last line): 8. p 9. Go to line 10: 10. :10 11. Pull 3 lines into the buffer: 12. 3yy 13. Now move to the second line: 14. :2 15. Place the contents of the buffer after the second line: 16. p 17. Delete lines 15-20. First, go to line 15. 18. :15 19. Now delete 6 lines: 20. 6dd Nouhad J. Rizk Operating system 11/14 21. Moving text is done by combininig deletion with placement. Move lines 25-26 to the bottom of the file as follows. 22. :25 23. 2dd 24. G 25. p 26. Join the top two lines as follows: 27. :1 28. J 29. Join 3 lines (current plus next two): 30. 3J 31. Move your cursor to somewhere in the middle of the newly joined line, and delete everything past the location of the cursor, by hitting capital D 32. Go to column 1 of the current line, by hitting number 0 33. Go to the end of the current line, by hitting the key $ 34. Go to the top of the file, by entering :1 35. Change all occurrences of the word line to stuff 36. :%s/line/stuff/g 37. Turn line numbers on: 38. :set nu 39. Turn them off again: 40. :set nonu 41. Continue experimenting with basic editing commands as you like. 42. Save your changes periodically by entering :w 43. When you are through, save and quit by entering :wq Editing across files 1. Edit test.file 2. vi test.file Nouhad J. Rizk Operating system 12/14 3. Turn line numbers on 4. :set nu 5. Save lines 11-20 into a new file called new.file 6. :11,20w new.file 7. From the first edit session, edit new.file, to verify that you correctly saved lines 11-20. 8. :e new.file 9. Return to the first edit session for test.file 10. :e # 11. Now use a named buffer, to transfer lines 1-10 from test.file to new.file. The buffer can be named a. First, go to the top of test.file :1 12. Retrieve 10 lines into named buffer a. 13. "a10yy 14. Edit new.file 15. :e new.file 16. Go to the top of new.file 17. :1 18. Retrieve the contents of buffer a, and place them prior to the top line Nouhad J. Rizk Operating system 13/14 19. "aP 20. Return to test.file 21. :e # 22. Append lines 10-12 to the end of new.file 23. :10,12w>> new.file 24. Verify that the new lines were appended, by editing the alternate file (new.file) and going to the bottom. 25. :e # 26. G 27. Save and quit: 28. :wq Create a vi profile (.exrc) 1. At the UNIX command prompt, make sure you are in your home directory: 2. cd $HOME 3. Create a .exrc file: 4. vi .exrc 5. Go into input mode, by hitting letter i 6. Type the following text: 7. set showmode 8. Optional: If you want line numbers to always be displayed, then hit the return key, and enter the text set nu. 9. set nu Nouhad J. Rizk Operating system 14/14 10. Return to command mode by hitting the ESC key 11. Save and quit by entering :wq 12. Now test your profile, by opening test.file: 13. vi test.file 14. Go into input mode, by hitting letter i. You should see INPUT MODE in the bottom right. 15. Hit the ESC key to return to command mode. 16. Hit capital R (shift-R) to go to replace mode. You should see REPLACE MODE at the bottom right. 17. Return to command mode, by hitting the ESC key. 18. Save and quit by entering :wq Log out If you are finished now, remember to logout at the UNIX command prompt: logout