How do I insert sequential line numbers using visual block mode?

Explanation

By combining visual block insert with Vim's expression register, you can insert dynamically computed line numbers at the start of each selected line. The expression register (=) evaluates a Vimscript expression for each line, allowing sequential numbering.

How it works

• <C-v>jj — select lines in block mode
• I — enter insert mode at the start of the block
• <C-r>= — invoke the expression register
• printf('%02d ', line('.')-line("'<")+1) — calculates the relative line number, zero-padded
• <CR><Esc> — confirm expression and apply to all lines

Example

Before:
apple
banana
cherry

After:
01 apple
02 banana
03 cherry

Tips

• Use g<C-a> on a visual selection of zeros for a simpler numbering approach
• Change the printf format for different styles: '%d. ' for 1. 2. 3.
• line("'<") gives the first line of the selection for relative numbering
• For absolute line numbers, just use line('.') without the offset