Cheatsheet Pages / Regex Cheatsheet
What does . match in regex? Any character except a newline
You need a wildcard: one character, any character, in a known position.
Patterns use the syntax shared by PCRE / Python / JavaScript; engine differences are flagged in the cheatsheet where they matter. Test any pattern at regex101.com — and pick the matching engine.
a.c
# matches: abc, a1c, a-c … but not "ac" or "a\nc"