How do I filter the output of an Ex command to show only matching lines?

Explanation

The :filter command restricts the output of another Ex command to only lines matching a given pattern. It works like piping through grep but entirely within Vim, and it applies to any command that produces multi-line output.

How it works

• :filter /pattern/ {cmd} — show only output lines matching pattern
• :filter! /pattern/ {cmd} — invert the filter, showing lines that do NOT match
• The pattern uses Vim's regular expression syntax
• {cmd} can be any Ex command that produces output: :ls, :marks, :map, :highlight, :set, etc.

Example

To see only modified buffers:

:filter /+/ ls

To list only mappings that involve <Leader>:

:filter /Leader/ map

To show all highlight groups containing "Comment":

:filter /Comment/ highlight

To see all settings related to "tab":

:filter /tab/ set all

Tips

• Use :filter! (with bang) to exclude matching lines instead — the inverse filter
• Especially powerful with :ls, :marks, :registers, :map, and :autocmd which produce verbose output
• Combine with :verbose for even more detail: :filter /pattern/ verbose map
• Available in Vim 8.0+ and all Neovim versions