How do I force a search to be case-sensitive even when ignorecase is enabled?

Explanation

Adding \C anywhere in a search pattern forces case-sensitive matching for that search, overriding the global ignorecase setting. It is the uppercase counterpart to \c (which forces case-insensitive matching) and gives you per-search control over case sensitivity.

How it works

• :set ignorecase (or :set ic) — makes all searches case-insensitive by default
• \c in a pattern — forces case-insensitive for that specific pattern
• \C in a pattern — forces case-sensitive for that specific pattern, regardless of ignorecase or smartcase

\C can appear anywhere in the pattern — at the start, middle, or end. /Foo\C, /F\Coo, and /\CFoo are all equivalent.

Example

With :set ignorecase active and this buffer:

apple Apple APPLE

• /apple — matches all three (case-insensitive due to ignorecase)
• /apple\C — matches only apple (case-sensitive forced by \C)
• /Apple\C — matches only Apple

Tips

• Useful with smartcase: smartcase only enables case-sensitivity when your pattern contains uppercase, but \C lets you force sensitivity even for all-lowercase patterns like /id\C to find id but not Id or ID
• Works in substitute patterns: :%s/foo\C/bar/g replaces only lowercase foo
• Works in :vimgrep, :global, and any other command that takes a pattern
• To force case-insensitive on a per-search basis (the reverse), use \c