[Solved] Replacing a letter inside a word

[clausisme]

Some time ago there was a grammatical change in the way some words are written in romanian. Here is one of these rules:
- when inside a word î turns into â like: cît > cât. But only when inside a word, this does not apply when it's at the beginning or at the end of the word like this: încît > încât.

I have some old books and I need to use a replace command in writer.

[acknak]

This works for me with your example:

Edit > Find & Replace
Search for: (?<=\w)î(?=\w)
Replace with: â
Options/Regular expressions: ON

Click Replace All

The patterns around the î are "lookbehind" and "lookahead" elements that require a "word" character, \w, before and after the letter, but they don't include the word characters in the actual match, so they are not replaced.

These pattern elements are explained here (for example):
https://www.regular-expressions.info/lookaround.html

[clausisme]

Thank you. That worked.