Tips & Tricks: Formatting

Normal mode commands can be used to apply an operation over each line in a range . Suppose you are creating a list in python by yanking and pasting some content from another buffer . After pasting, the items are in place but are missing the trailing , required by python: Initial Conditions a = [ "one" "two" "three" ] NORMAL 33% 2:1 These could be manually added in various ways, but Vim's :normal command provides a handy solution by allowing a normal mode command to be applied to each line in a range. To demonstrate, we first create a visual selection: Select Visual Range v 2j a = [ "one" "two" "three" ] VISUAL 67% 4:1 Note that the range could have also been entered manually. Next create the command to execute. We would like to move the cursor to the end of each line, enter insert mode after the line, then enter the , character. Inserting after the line can be achieve with the A command, so the command to execute for each line is: A, and the complete command is: :normal A, Executing this command in our buffer provides the desired result: Execute the Command a = [ "one", "two", "three" , ] NORMAL 67% 4:12

Vim's internal formatting features work great in many cases, but sometimes it can be helpful to send a buffer's content to an external program to perform the formatting, then replace the buffer contents with the result. For example, suppose we have the following JSON file in a buffer and want to sort the keys. Initial Conditions { "bananas": 12, "strawberries": 15, "apples": 34, "oranges": 24, "grapes": 33 } COMMAND Top 1:1 :%!jq -S . % We will demonstrate how to achieve this using a command-line mode command that calls jq , a popular command-line JSON processor. Obviously jq needs to be installed on a system for this to work. The command to execute is: :%!jq -S . % 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. 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: jq -S . % The details of this command are (mostly) outside the scope of Vim itself, but can be found by executing jq --help which indicates that the jq command is called with the format: jq [options] <jq filter> [file] where: [options] = -S (sort object keys) <jq filter> = . (pass all lines back to stdout) [file] = % (Vim inserts the current filename) Now, when we execute this command we get the following result: After External Formatting { "apples": 34, "bananas": 12, "grapes": 33, "oranges": 24, "strawberries": 15 } NORMAL Top 1:1 7 lines filtered which contains our sorted JSON object.

Starting with the cursor in the middle of an un-formatted buffer : Initial Conditions <div> <p>line one</p> <p>line two</p> <p>line three</p> </div> NORMAL 50% 3:1 The first step is to execute gg , which moves the cursor to the top of the buffer: Move to Top of Buffer g g < div> <p>line one</p> <p>line two</p> <p>line three</p> </div> NORMAL Top 1:1 Next, we execute = , which tells Vim to format the lines traversed by the associated motion. We follow this with G , which indicates that we want to apply formatting from the current line to the bottom of the file: Format the Entire Buffer = G < div> <p>line one</p> <p>line two</p> <p>line three</p> </div> NORMAL Top 1:1 5 lines indented The end result shows that the combination of gg and G includes all lines in the file.

Starting with the cursor in the middle of an un-formatted buffer : Initial Conditions <div> <p>line one</p> <p>line two</p> <p>line three</p> </div> NORMAL 50% 3:1 Enter visual mode : Enter Visual Mode <Esc> <div> <p>line one</p> <p>line two</p> <p>line three</p> </div> NORMAL 50% 3:1 Move down another row: Create the Selection v <div> <p>line one</p> <p>line two</p> <p>line three</p> </div> VISUAL 50% 3:1 and finally format the selected lines: Format Selection j <div> <p>line one</p> <p>line two</p> <p>line three</p> </div> VISUAL 67% 4:1 Note that Vim formatted only the lines contained within the selection (including lines containing the cursors), and didn't touch the other lines.

When editing text documents, paragraphs can often become split up into lines of varying lengths. For example, starting from the following text: Initial Conditions T his is a single paragraph with lines that have been split up into different lengths. NORMAL Top 1:1 One solution is to combine Vim's text formatting command gw with the paragraph text object selector ip : gw{motion} tells Vim to format the lines that covered by {motion}, and the ip [[text object]] tells Vim to apply this formatting over the inner paragraph . Reflow g w i p T his is a single paragraph with lines that have been split up into different lengths. NORMAL Top 1:1 The lines of the paragraph are combined, then split at word boundaries to produce a sequence of lines with lengths that follow the width set by vim.opt.textwidth .