How do I use the filename under the cursor as a value in a Vim mapping or command?

Explanation

The expand('<cfile>') function returns the filename that Vim sees under the cursor — the same file that gf would open. Unlike the % register (which gives the current buffer's path), <cfile> extracts a path-like string from the text at the cursor position. This makes it useful for building mappings that act on file references embedded in your code or documentation.

How it works

• expand('<cfile>') — returns the filename under the cursor as a string
• expand('<cWORD>') — returns the full WORD under the cursor (less intelligent)
• expand('<cfile>:p') — applies filename modifiers; :p expands to the full absolute path
• Vim uses 'path' and 'suffixesadd' when resolving <cfile>, just like gf

Example

Map a key to open a vertical split for the file under the cursor:

nnoremap <leader>gv :vsplit <C-r>=expand('<cfile>')<CR><CR>

Or search for a file across your project using the name under the cursor:

nnoremap <leader>ff :find <C-r>=expand('<cfile>')<CR><CR>

Tips

• <C-r>=expand('<cfile>')<CR> inserts the result into the command line interactively, letting you edit it before executing
• Combine with fnamemodify() for more complex path transformations: fnamemodify(expand('<cfile>'), ':r') strips the extension
• <cfile> respects 'iskeyword' and path separators, so it picks up ../foo/bar.lua as a whole unit
• Unlike %, <cfile> works correctly even when the cursor is not in the current file's path