How to quickly change variable names in Vim?

Question

I am using Vim to read through a lot of C and Perl code containing many single letter variable names.

It would be nice to have some command to change the name of a va

Answer 1

Put this in your .vimrc

" Function to rename the variable under the cursor
function! Rnvar()
  let word_to_replace = expand("")
  let replacement = input("new name: ")
  execute '%s/\(\W\)' . word_to_replace . '\(\W\)/\1' . replacement . '\2/gc'
endfunction

Call it with :call Rnvar()

expand("") gets the word under the cursor. The search string uses % for file-scope, and the \(\W\) patterns look for non-word characters at the boundary of the word to replace, and save them in variables \1 and \2 so as to be re-inserted in the replacement pattern.