How do I dynamically build and run Ex commands from strings in Vim?

Explanation

The :execute command evaluates a string as an Ex command, enabling dynamic command construction. You can build commands using variables, expressions, and concatenation, making it the cornerstone of Vimscript metaprogramming.

How it works

• :execute {string} — evaluates the string as an Ex command
• Strings can be concatenated with . operator
• Variables and expressions are interpolated when building the string
• Nested execute calls are supported

Example

" Dynamic normal mode command
:let count = 5
:execute 'normal! ' . count . 'j'

" Dynamic substitution
:let old = 'foo'
:let new = 'bar'
:execute '%s/' . old . '/' . new . '/g'

" Open file from variable
:let fname = 'config.yml'
:execute 'edit ' . fname

Tips

• Use execute to run commands with special characters that are hard to type literally
• Combine with normal! (with bang) to avoid triggering user mappings
• execute can run multiple commands separated by |
• Use fnameescape() when using filenames: :execute 'edit ' . fnameescape(name)