How do I join multiple selected lines into one line using visual mode?

Explanation

Select lines in Visual mode and press J to join them into a single line. Vim removes the line breaks and inserts a single space between each joined line (or no space if the line ends with whitespace). gJ joins without adding any spaces.

How it works

1. Select lines with V (Visual Line) or v (Visual Character)
2. Press J to join them

Example

Given:

Hello
World
from
Vim

Select all 4 lines (ggVG), press J:

Hello World from Vim

With gJ instead:

HelloWorldfromVim

Normal mode variants

• J in Normal mode joins the current line with the next one
• 3J joins the current line with the next 2 lines (3 lines total)
• gJ in Normal mode joins without spaces

Tips

• J is smart about trailing whitespace and leading spaces — it collapses them into a single space
• If a line ends with ., !, or ?, J inserts two spaces (sentence-aware joining) — disable with :set nojoinspaces
• For joining with a custom delimiter, use a substitution instead: :'<,'>s/\n/, / joins lines with ,
• J in visual mode is the fastest way to un-wrap a paragraph that was hard-wrapped at 80 columns