How do I create my own custom Ex commands in Vim?

Explanation

:command defines a user-defined Ex command — a custom command that you invoke with :Name just like built-in commands. User commands must start with an uppercase letter (to distinguish them from built-in commands which are all lowercase). This is the foundation for creating convenient shortcuts, project-specific workflows, and plugin interfaces.

Basic syntax

:command {Name} {replacement}

Examples

Create a command to strip trailing whitespace:

:command! TrimWhitespace %s/\s\+$//e

Now :TrimWhitespace works like a built-in command.

Create a command that takes arguments:

:command! -nargs=1 Grep vimgrep /<args>/ **/*

Usage: :Grep TODO searches all files for TODO.

Create a command with a range:

:command! -range=% JSONFormat <line1>,<line2>!python3 -m json.tool

Usage: :'<,'>JSONFormat or :%JSONFormat

Flags

Tips

• :command (no args) lists all user-defined commands
• :delcommand {Name} removes a user command
• Use <q-args> for quoted arguments, <f-args> for function call arguments
• :command! (with bang) silently overwrites — use this in vimrc to avoid errors on re-source