Vim Substitute Command Flags, Ranges and Patterns

Professor Smith criticized Professor Johnson today. ~ to: Teacher Smith criticized Professor Johnson today. ~ To change every occurrence on the line, you need to add the g (global) flag. The command: > :%s/Professor/Teacher/g results in (starting with the original line): Teacher Smith criticized Teacher Johnson today. ~ Other flags include p (print), which causes the ":substitute" command to print out the last line it changes. The c (confirm) flag tells ":substitute" to ask you for confirmation before it performs each substitution. Enter the following: > :%s/Professor/Teacher/c Vim finds the first occurrence of "Professor" and displays the text it is about to change. You get the following prompt: > replace with Teacher? (y)es/(n)o/(a)ll/(q)uit/(l)ast/scroll up(^E)/down(^Y) At this point, you must enter one of the following answers: y Yes; make this change. n No; skip this match. a All; make this change and all remaining ones without further confirmation. q Quit; don't make any more changes. l Last; make this change and then quit. CTRL-E Scroll the text one line up. CTRL-Y Scroll the text one line down. The "from" part of the substitute command is actually a pattern. The same kind as used for the search command. For example, this command only substitutes "the" when it appears at the start of a line: > :s/^the/these/ If you are substituting with a "from" or "to" part that includes a slash, you need to put a backslash before it. A simpler way is to use another character instead of the slash. A plus, for example: > :s+one/two+one or two+ ============================================================================== *10.3* Command ranges The ":substitute" command, and many other : commands, can be applied to a selection of lines. This is called a range. The simple form of a range is {number},{number}. For example: > :1,5s/this/that/g Executes the substitute command on the lines 1 to 5. Line 5 is included. The range is always placed before the command. A single number can be used to address one specific line: > :54s/President/Fool/ Some commands work on the whole file when you do not specify a range. To make them work on the current line the "." address is used. The ":write" command works like that. Without a range, it writes the whole file. To make it write only the current line into a file: > :.write otherfile The first line always has number one. How about the last line? The "$" character is used for this. For example, to substitute in the lines from the cursor to the end: > :.,$s/yes/no/ The "%" range that we used before, is actually a short way to say "1,$", from the first to the last line. USING A PATTERN IN A RANGE Suppose you are editing a chapter in a book, and want to replace all occurrences of "grey" with "gray". But only in this chapter, not in the next one. You know that only chapter boundaries have the word "Chapter" in the first column. This command will work then: > :?^Chapter?,/^Chapter/s=grey=gray=g You can see a search pattern is used twice. The first "?^Chapter?" finds the line above the current position that matches this pattern. Thus the ?pattern? range is used to search backwards. Similarly, "/^Chapter/" is used to search forward for the start of the next chapter. To avoid confusion with the slashes, the "=" character was used in the substitute command here. A slash or another character would have worked as well. ADD AND SUBTRACT There is a slight error in the above command: If the title of the next chapter had included "grey" it would be replaced as well. Maybe that's what you wanted, but what if you didn't? Then you can specify an offset. To search for a pattern and then use the line above it: > /Chapter/-1 You can use any number instead of the 1. To address the second line below the match: > /Chapter/+2 The offsets can also be used with the other items in a range. Look at this one: > :.+3,$-5 This

This section expands on the `:substitute` command in Vim, explaining the use of flags like 'p' for printing the last changed line and 'c' for interactive confirmation. It also details the available options at the confirmation prompt (y/n/a/q/l/CTRL-E/CTRL-Y). The use of search patterns in the 'from' part of the substitute command is explained, along with the use of alternative delimiters to the slash. The section covers command ranges specifying which lines the command applies to, including using line numbers, '.', '$', and '%' for current line, last line, and all lines respectively. It also demonstrates using patterns in ranges to select lines, and how to add or subtract lines relative to a pattern match.