Tips & Tricks: Editing

Reorganizing lines in a buffer is a very common task. While a yank and paste sequence could be used for each line, there is a better way. The following keymaps allow a line or group of lines to be easily moved up or down using a single keystroke: -- single-line vim . keymap . set ( "n" , "<A-j>" , ":move .+1<CR>==" ) vim . keymap . set ( "n" , "<A-k>" , ":move .-2<CR>==" ) -- multi-line vim . keymap . set ( "v" , "<A-j>" , ":move '>+1<CR>gv=gv" ) vim . keymap . set ( "v" , "<A-k>" , ":move '<-2<CR>gv=gv" ) To see how they work, consider the following buffer: Initial Conditions a = [ "one", "three", "two", "four", "five", ] NORMAL Top 1:1 Note that the words are out of order, and we would like to fix that. We start by moving the cursor to the line that we want to move (i.e. the "target" line): Move to Target Line 2j a = [ "one", "three", "two", "four", "five", ] NORMAL 38% 3:1 With this keymap, hitting A-J allows us to easily move the currently down one position, swapping its position with the line below it: Move Current Line <A-j> a = [ "one", "two", "three", "four", "five", ] NORMAL 50% 4:1 To get a better idea about what happened, consider the command that executed when we hit A-J : :move .+1<CR>== The :move command has a call signature: :m[ove] {address} and moves the current line (or selected lines) to the line below the specified address. In this case, the specified address is .+1 , which we learned in the ranges chapter means "the line below the current line". The carriage return causes the preceding command to execute, which is follows by == , which formats (indents) the line after it is moved. Let's see how this works with a visual selection . First, let's move the cursor so that the selection spans three lines: Select Multiple Lines v 2j a = [ "one", "two", "three", "four", "five", ] VISUAL 75% 6:1 Note that although the selection only touches the third line, the entire line is included in the block of lines to move. Now, move these lines up: Move Multiple Lines <A-k> a = [ "one", "three", "four", "five", "two", ] VISUAL 62% 5:1 3 lines indented The selected lines have each move up one line, and the line containing "two" (which has previously been above the selection) is now located below the selection.

Occasionally while editing a document the need to prepend text to a sequence of lines comes up. For example, suppose you want to comment out some lines in a file by prepending each line with a "#" character. A simple way to achieve this is to leverage normal mode commands to apply an operation over each line in a range . To demonstrate, let's start with the following file: Initial Conditions o ne two three four five six NORMAL Top 1:1 First let move the cursor down a few lines and make a visual selection : Make Selection 2jV2j o ne two three four f ive six V-LINE 71% 5:1 Now that we have selected the lines to modify, let's build our command. First, hit : to enter command-line mode then enter normal to indicate that this command should execute in normal-mode. This tells Neovim that the following command should be executed once for each line in the selection. Finally, we type the same keystrokes that we would execute in normal mode to achieve the desired changes. In this case, we want to execute I to move the cursor to the beginning of each line and enter insert mode , then # to insert this character. :norm I# Before Executing Command one two three four f ive six COMMAND 71% 5:1 :normal I# After executing this command, we can confirm that a "#" has been inserted at the start of each line in the selection. After Executing Command one two #three #four # five six NORMAL 71% 5:1

A common task when editing files is to remove duplicate lines. While this can be done manually, it is often easier to leverage Vim's command-line mode to leverage the uniq command. Suppose we have the following file in a buffer and want to remove duplicates: Initial Conditions b ananas apples apples oranges apples COMMAND Top 1:1 :%!uniq The command to execute is: :%!uniq Let's break this down to review what is happening: To start, this follows the pattern: :[range]!{cmd} {args} where :% specifies the range as the entire file, although this can be replaced with a range specifying a subset of lines, or a visual selection . Next, !{cmd} indicates that an external command is to be called with the specified range and arguments. In this case the external command to be called is: uniq with (initially) no arguments. By default uniq takes input from stdin , so there is no need to specify the input source. Executing this command produces the following output: Execute uniq b ananas apples oranges apples NORMAL Top 1:1 5 lines filtered which is not exactly what we were looking for. It turns out that by default uniq only detects adjacent repeating lines, so apple still appears twice in the output. If we take a look at the help page for uniq we see that the -u option can be used to print only unique lines, which is what we were looking for. Lets undo to get back to the original buffer, then try again using the -u argument: Execute uniq -u b ananas oranges apples NORMAL Top 1:1 5 lines filtered That is more like it. We should note that uniq also offers the -d option, which performs the opposite function and returns only the duplicate lines . Starting from the original buffer we can execute this command to see the result: Execute uniq -d a pples NORMAL Top 1:1 5 lines filtered

It is a common task to search and replace all occurrences of a word within the current buffer. For example, given the following buffer : Initial Conditions B eautiful is better than ugly. Explicit is better than implicit. Simple is better than complex. Complex is better than complicated. Flat is better than nested. Sparse is better than dense. Readability counts. COMMAND Top 1:1 :%s/is/is way/ Suppose one wants to change all occurrences of is better to is way better . The general template for searching and replacing is: :[range]s/{pattern}/{replacement}/[flags] where Template Value Description : Puts Vim into Command Mode [range] % Applies this command to the entire file s/ Indicates that this is a search and replace operation {pattern}/ is Specifies the pattern to search for {replacement}/ is way Specifies the text to replace the search pattern with. [flags] No flags are specified. Putting this all together and executing the command: Title B eautiful is way better than ugly. Explicit is way better than implicit. Simple is way better than complex. Complex is way better than complicated. Flat is way better than nested. S parse is way better than dense. Readability counts. NORMAL 75% 6:1 6 substitutions on 6 lines As expected, each occurrence of is has been replaced with is way . Writing patterns can sometimes require a bit of trial and error, if the final text is not as expected, simply hit u to return to the original: Title u B eautiful is better than ugly. Explicit is better than implicit. Simple is better than complex. Complex is better than complicated. Flat is better than nested. S parse is better than dense. Readability counts. NORMAL Top 1:1 6 changes; before #1 0 seconds ago

It is a common task to search and replace all occurrences of a word within the current buffer. In some cases it can be convenient to use replacement text that is stored in a register. This tip demonstrates how to do so. Starting with the following buffer, note that we have already stored the replacement text in register A. Initial Conditions B eautiful is better than ugly. Explicit is better than implicit. Simple is better than complex. Complex is better than complicated. Flat is better than nested. Sparse is better than dense. Readability counts. NORMAL Top 1:1 :reg a Type Name Content l  "a   is way Now, to execute the replacement, we follow the standard replacement pattern:, :s/{pattern}/{replacement} where the replacement text references the contents of a register. Although in NORMAL mode we access a register's contents using "{register} , the search is executed in COMMAND mode. We can access register contents in COMMAND mode as follows: Command Action C-R {regname} insert the contents of a register or object under the cursor as if typed In order to access the contents of register a , we would therefore use a replacement spec of <C-R> a Search and Replace B eautiful is way better than ugly. Explicit is way better than implicit. Simple is way better than complex. Complex is way better than complicated. Flat is way better than nested. S parse is way better than dense. Readability counts. NORMAL 75% 6:1 6 substitutions on 6 lines Executing this command replaces each occurrence of is with the contents of register a , is way .

It is a common task to search and replace all occurrences of a word within the current buffer. For example, given the following buffer: Initial Conditions B eautiful is better than ugly. Explicit is better than implicit. Simple is better than complex. Complex is better than complicated. Flat is better than nested. Sparse is better than dense. Readability counts. NORMAL Top 1:1 Suppose one wants to change all occurrences of is better to is way better . The first step in the example if to move the cursor to the word we want to replace: w B eautiful i s better than ugly. Explicit is better than implicit. Simple is better than complex. Complex is better than complicated. Flat is better than nested. Sparse is better than dense. Readability counts. NORMAL Top 1:11 then press & to select all occurrences of the word under the cursor. In addition to selecting all occurrences of is , the cursor moves to the next occurrence. * Beautiful i s better than ugly. Explicit i s better than implicit. Simple is better than complex. Complex is better than complicated. Flat is better than nested. Sparse is better than dense. Readability counts. NORMAL 25% 2:10 The general template for searching and replacing is: :[range]s/{pattern}/{replacement}/[flags] where Template Value Description : Puts Vim into Command Mode [range] % Applies this command to the entire file s/ Indicates that this is a search and replace operation {pattern}/ Not needed, since the words to replace are already selected. {replacement}/ is way Specifies the text to replace the search pattern with. [flags] No flags are specified. Putting this all together and executing the command: Beautiful is way better than ugly. Explicit i s way better than implicit. Simple is way better than complex. Complex is way better than complicated. Flat is way better than nested. S parse is way better than dense. Readability counts. NORMAL 75% 6:1 6 substitutions on 6 lines As expected, each occurrence of is has been replaced with is way .