regex101: PCRE (Legacy) Match Workspace

Pro

(?m)applies the following effective flags to the remainder of the pattern: gm

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

^start of line

\h{2}any horizontal whitespace character, repeated exactly 2 times

\Sany non-whitespace character

.*any character (except for line terminators), repeated any number of times

Positive Lookahead(?=(?:\R\h{4}.*)*?\R\h{4}- potato_smf1)

Non-Capturing Group(?:\R\h{4}.*)*?

*?repeats the group contents below any number of times:

\Ra newline sequence

\h{4}any horizontal whitespace character, repeated exactly 4 times

.*any character (except for line terminators), repeated any number of times

\Ra newline sequence

\h{4}any horizontal whitespace character, repeated exactly 4 times

- potato_smf1the literal text - potato_smf1 (case sensitive)

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

25 tokens

Regular Expression

(?m)^\h{2}\S.*(?=(?:\R\h{4}.*)*?\R\h{4}- potato_smf1)

New

mysql_databases:
  potato_mychat1:
    - potato_mychat1
  potato_phpb1:
    - potato_phpb1
    - potato_smf1
  potato_phpb2:
    - potato_phpb2
  p_phpb282:
    - potato_phpb282
  potato_registry:
    - potato_registryadmi
  potato_smf1:
    - potato_smf1
  potato_smf2:
    - potato_smf2
  potato_wp82:
   - potato_wp82

Substitution

mysql_databases:
  potato_mychat1:
    - potato_mychat1
  potato_phpb1:
    - potato_phpb1
    - potato_smf1
  potato_phpb2:
    - potato_phpb2
  p_phpb282:
    - potato_phpb282
  potato_registry:
    - potato_registryadmi
  potato_smf1:
    - potato_smf1
  potato_smf2:
    - potato_smf2
  potato_wp82:
   - potato_wp82