How do I title-case every word in a buffer using one Vim substitution?

Explanation

When you need to normalize casing across headings, labels, or generated docs, editing words one by one is tedious. This substitution converts each word to title case in a single pass: first letter uppercase, remainder lowercase. It is a practical cleanup step after importing noisy text from external tools.

How it works

:%s/\v<(\w)(\w*)>/\u\1\L\2/g

• :%s targets the whole buffer
• \v enables very-magic regex syntax
• <(\w)(\w*)> matches each word boundary and splits the word into first character plus remainder
• \u\1 uppercases capture group 1 (the first letter)
• \L\2 lowercases capture group 2 (the rest of the word)
• g applies this to every word occurrence on each line

Example

Before:

ERROR LEVEL summary
second LINE OF TEXT

After:

Error Level Summary
Second Line Of Text

Tips

• To avoid touching short acronyms, run with c and confirm selectively
• Restrict the range (for example :10,40s/...) when you only want part of a file normalized
• Combine with marks so you can jump back to your original editing location quickly